# Attempting to Breed Microcrabs



## calebkraft (Jan 3, 2012)

I'll be watching this. It is quite fascinating that most people have the same exact result at a specific amount of time. There has to be something missing from the environment at that precise point of development.


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## msjinkzd (May 12, 2007)

can't wait to see you have success!


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## jasonpatterson (Apr 15, 2011)

calebkraft said:


> I'll be watching this. It is quite fascinating that most people have the same exact result at a specific amount of time. There has to be something missing from the environment at that precise point of development.


Indeed. I'm hoping that something in the grab bag of stuff I've got going in that tank does the trick. There is plenty of wood, leaves, lots of microfauna, TONS of floaters (my RRF has been taking over once a week for the past 4 months...) some stems, moss, and recently, unfortunate quantities of algae. 

If nothing else, I watch the tank several times a day and am hoping to catch the zoeas free floating. If that happens I can pipette them out into a growout tank and try to feed them directly. I've got all sorts of stuff to try on them, from fresh and marine phyto to wheat chaff infusoria from my garden. I expect lots of frustration before I ever get a hint of success, but I would love to see the first step actually happen and have a chance to fail.

Should have mentioned this, but I'm keeping them in a tank with pH 6.8, GH 4, KH 1, and temperature 73F. I'm concerned that it might be too cold for them, but I've got shrimp in the same tank that I'm also trying to work with that need the cooler temperatures. I love looking at my aquariums, but I much prefer actually working with the animals. I feed the tank flake food, sinking crab pellets, spinach and/or turnip greens (or whatever I pick from the yard when it's the right time of the year), algae wafers, and bloodworms once in a while.


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## jone (Nov 27, 2011)

just a thought to consider...at the very point in time the female is ready to release all the zoeas,,I would automatically think what is the water current in the tank is???? my thinking is they would have to stay free floating with minimal effort exspended..if they exert to much energy staying free floating then they would problably die before they can actually hunt food..just trying to help,,,hopefully just a thought to think of...


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## jasonpatterson (Apr 15, 2011)

It's certainly worth considering. I know that amano zoeas are reasonably strong swimmers. I just don't know anything about these yet, honestly.  Thanks for the suggestion.


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## mistergreen (Dec 9, 2006)

I will do his in the spring when it's warmer.

Do you have any filtration? I'm thinking any mechanical filtration will be bad, sucking in the zoeas. If raising them is like raising daphnia, use aged water only and don't use contaminated (excel, H2O2, medicated) tank water.


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## mordalphus (Jun 23, 2010)

jasonpatterson said:


> It's certainly worth considering. I know that amano zoeas are reasonably strong swimmers. I just don't know anything about these yet, honestly.  Thanks for the suggestion.


My zoae were always gathered at the top of the tank during the day whenever I saw them, usually in a corner. I tried feeding powdered spirulina, but either it wasn't appetizing, or just too big for them to eat because they'd always disappear after a few days. I was going to try chlorella, but ended up putting the adults into a container pond outdoors where they were promptly destroyed by dragonfly larvae *GRRRR*, this year, they'll be going into a container pond with a SCREEN on it.

I wish you luck! Would be great if someone could breed them indoors!


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## Soothing Shrimp (Nov 9, 2011)

Have you tried growing algae on the glass as well?


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## msjinkzd (May 12, 2007)

Jason, keep an eye on those ladies. I found zoae this morning in my crab tank.


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## DesmondTheMoonBear (Dec 19, 2011)

msjinkzd said:


> Jason, keep an eye on those ladies. I found zoae this morning in my crab tank.


What do they look like?


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## msjinkzd (May 12, 2007)

little dots that move in a floaty erratic motion. If I hadn't broken my speedlight I could take pics *frustrated*

They are in a green water tank, with lots of algae on teh walls and a 24 hour light, we will see.


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## jasonpatterson (Apr 15, 2011)

mordalphus said:


> My zoae were always gathered at the top of the tank during the day whenever I saw them, usually in a corner. I tried feeding powdered spirulina, but either it wasn't appetizing, or just too big for them to eat because they'd always disappear after a few days. I was going to try chlorella, but ended up putting the adults into a container pond outdoors where they were promptly destroyed by dragonfly larvae *GRRRR*, this year, they'll be going into a container pond with a SCREEN on it.
> 
> I wish you luck! Would be great if someone could breed them indoors!


Thanks for the good vibes. I've got spirulina and will likely offer that as a later food. I've also got the smallest of the golden pearl varieties, which might suit a crab's diet better. 



Soothing Shrimp said:


> Have you tried growing algae on the glass as well?


It's not so much a matter of trying to grow it as trying to keep it under control. 



msjinkzd said:


> Jason, keep an eye on those ladies. I found zoae this morning in my crab tank.


Going to go check them out right now. ETA: No babies found tonight. I stopped the filter for 5 minutes or so and put the room into complete darkness. I then put a flashlight on one corner of the tank and waited a few minutes. There were a number of tiny crustaceans, but nothing that looked like what I thought a crab zoea ought to. The presence of healthy microfauna also helps put to rest concerns about filtration.

I missed a multiquote, but yes, the 20L is filtered. It's got a good prefilter sponge on there, and I haven't had problems with amano zoeas being sucked into it previously. I don't know about the size difference between the zoeas of the two species though, so it's worth considering. The smaller tanks are not; I've been using pieces of lava rock in the bottom as super low quality filters. They have been aged and are thoroughly covered in bacteria, whether they help keep the tanks in good shape or not remains to be seen. I was using bottles filled with lava rock as filters, but the microcrabs are able to get into even the tiniest of gaps/inlets in the bottles and hide inside. I wound up having to carefully cut them all apart to try to find the potential mothers.


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## jasonpatterson (Apr 15, 2011)

Still no zoeas, not from the two berried females I have isolated in a hatching tank nor from the remaining four females that are berried in the main tank. I check several times a day, before, during, and after the lights are in use as well. I had two females drop their eggs (I think) right after they got in the tank, but at the same time I believe that I've seen numerous instances of mating going on as well, so I expect the number of berried crabs to remain strong.


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## shrimpo (Aug 2, 2009)

I thought zoeas need brackish water in order to fully develop into crab.


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## aquaponicpaw (Dec 9, 2011)

I read somewhere that in their natural habitat they reside in water hyacinth. It's an invasive species in my state. So once it warms up I will acquire some. Not sure how helpful this is. But I aquired this paper from franks Aquarium.


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## aquaponicpaw (Dec 9, 2011)

love these guys!


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## madness (Jul 31, 2011)

shrimpo said:


> I thought zoeas need brackish water in order to fully develop into crab.


zoea just references one of the stages that larval crustaceans go through.

It doesn't really have anything to do with whether or not they are fully freshwater.

The most common shrimp that go through larval stages that we deal with in the hobby (Amano shrimp, caridina propinqua shrimp) just happen to require brackish conditions for the zoea.


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## mistergreen (Dec 9, 2006)

aquaponicpaw said:


> I read somewhere that in their natural habitat they reside in water hyacinth. It's an invasive species in my state. So once it warms up I will acquire some. Not sure how helpful this is. But I aquired this paper from franks Aquarium.


Thanks for the paper. I have luck raising daphnia with water hyacinth and water letter. Their roots harbor lots of microbes the larvae can eat. I guess a 'dirty' tank is best to raise the larvae.


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## jasonpatterson (Apr 15, 2011)

aquaponicpaw said:


> I read somewhere that in their natural habitat they reside in water hyacinth. It's an invasive species in my state. So once it warms up I will acquire some. Not sure how helpful this is. But I aquired this paper from franks Aquarium.


They might use water hyacinths nowadays, but they definitely didn't evolve to do so, as water hyacinths are native to the Amazon. I read the same paper though, prior to keeping them. I've got gobs of red root floaters going in their tank. Very infrequently I catch the crabs hanging out in their roots. I've never seen one swim up to the top, but they must at some point in the day.

One thing I've noticed my most mature, hairiest crabs doing is filter feeding. They don't do so in the sense that bamboo shrimp do, i.e. they don't constantly clean their setae as they filter the water. Instead they rest with arms extended into the current and when a relatively large object hits, they grab it. I am a bit curious about what might occur if a very small shrimp wandered into an adult crab's arms. To be perfectly clear, in half a year of keeping them, they have yet to show the slightest aggression toward any other tank inhabitants.


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## shrimpo (Aug 2, 2009)

madness said:


> zoea just references one of the stages that larval crustaceans go through.
> 
> It doesn't really have anything to do with whether or not they are fully freshwater.


I meant the micro crab Zoea not zoae in general.
I read somewhere that the river current drive's them down to brackish water.


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## Chlorophile (Aug 2, 2011)

shrimpo said:


> I meant the micro crab Zoea not zoae in general.
> I read somewhere that the river current drive's them down to brackish water.


That is what I read also, except it was about amano shrimp.


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## jasonpatterson (Apr 15, 2011)

shrimpo said:


> I meant the micro crab Zoea not zoae in general.
> I read somewhere that the river current drive's them down to brackish water.


This is on the list of things to try if I ever manage to get a good batch of zoeas going, but everything I've seen or heard about them indicates that they live their entire lives in fresh water. Their genus name even means hairy lake dweller, loosely translated (limno- and -pilo, which I bothered to figure out before thinking to try to look it up. I found the source almost immediately. Stinking research, giving me answers to questions I'm curious about. The naiyanetri part is in honor of a Thai biologist, Phaibul Naiyenetr.) Here's the paper describing the genus and species for the first time. It's an anatomical rather than behavioral or environmental paper. 

The specimens from this paper were collected very near the ocean though, in so it's entirely possible that they have a brackish phase to their development. In fact, the species holotype was collected in a river filled area of Nakhon Pathom province not 15 miles from the Gulf of Thailand. This might be worth more than a casual look. Glad you asked or I never would have bothered to look at the map.


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## mistergreen (Dec 9, 2006)

Yeah, definitely put a bunch in a brackish solution and fw to see if one group lives longer than the other.

It might have nothing to do with the salinity but the type of food available in those environments.


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## shrimpo (Aug 2, 2009)

jasonpatterson said:


> This is on the list of things to try if I ever manage to get a good batch of zoeas going, but everything I've seen or heard about them indicates that they live their entire lives in fresh water...The specimens from this paper were collected very near the ocean though, in so it's entirely possible that they have a brackish phase to their development. In fact, the species holotype was collected in a river filled area of Nakhon Pathom province not 15 miles from the Gulf of Thailand. This might be worth more than a casual look. Glad you asked or I never would have bothered to look at the map.


I am thinking if its possible to adjust fully grown crabs to low end brackish water ~1.004 and let them breed in there so you don't have to move the zoea to another tank.


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## jasonpatterson (Apr 15, 2011)

Not much has been going on lately with these. Of the females that I captured and put in a small hatching tank, neither has done anything yet. One of them, the one that had only a very few eggs to start with, has either dropped or hatched her eggs without me noticing, so she was returned to the main tank. 

I did another full rescape today after discovering that floramax contains chips of carbonate rocks (they fizz wildly in vinegar) and has almost certainly been the source of my pH/KH headaches in that tank lately (numerous lost batches of bumblebee shrimp eggs and 0 surviving baby bumblebees in the last 2 months...) In the process of moving everything I was more concerned with speed than doing a proper head count, but it appears that most, if not all, of the crabs have survived to this point. I checked each as I moved them, and checked size, sex, and berried status. Of the females, all but 3 were berried. I left 3 berried females in the main tank and transferred the remaining berried females to my hatching tank to see if I could finally get some zoeas. I've seen numerous instances of mating behavior lately, so it seems likely that conditions are good for them to reproduce. Hopefully now that I rescaped I didn't mess things up overly much.

I've noticed a few things about these animals. I would like to be perfectly clear that these are just my observations and that it's entirely possible that they would be proven wrong with a larger or more representative sample of the animals.

Sexual dimorphism: Males appear to grow substantially larger than females. Of the crabs I have, the 5 largest are males, and they are larger by far than any of the remaining crabs. I have very few small males, and it seems likely that the small males that I have are young animals. The males also have much heavier claws and are much more setose (aka hairy.)

Color: RandomMan noted this in another microcrab thread recently. Microcrabs kept in soft, acidic water tend to turn gray. If they are kept in hard, basic water, they tend to turn brown.

Temperament: Peaceful, entirely so. The most aggressive acts I have seen involved mating, when the males occasionally use their claws to hold a female's leg, or when several microcrabs are in the same small container (as in shipping) they will tend to grab onto one another and form a crab ball. They disengage from the ball without injuring one another, however. While rescaping I tried repeatedly to get a crab to pinch me, they just wouldn't do it. I believe that one of my largest males managed to get me once, but his claw power was so weak that I am not certain whether that was what was happening or not.


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## Smokeygrey (Feb 17, 2012)

I'm reading and keeping tabs on this, as I'm interested to see the outcome to..

Someone needs to figure out how to breed these so we can start worrying about breeding some Color into them..


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## D3monic (Jan 29, 2012)

I would think about using a kreisel and freshwater rotifers if they are small enough. I know the marine ones I used to use would be but not sure on FW.


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## Warlock (Feb 28, 2012)

what inverts do you have with them!? they are safe with shrimp?!


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## lipadj46 (Apr 6, 2011)

Warlock said:


> what inverts do you have with them!? they are safe with shrimp?!


they are shrimp safe. I have 10 coming tomorrow to add to my shrimp tank.


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## Warlock (Feb 28, 2012)

lipadj46 said:


> they are shrimp safe. I have 10 coming tomorrow to add to my shrimp tank.


really.. 


very interesting..


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## aquaponicpaw (Dec 9, 2011)

Has anyone heard of/tried keeping them with CPOs? I would like to add some to my tank but Not sure. I tried a baby Marm But "it" immediately started seeking out the Crabs so I removed him before anything can happen.


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## jasonpatterson (Apr 15, 2011)

Still being thwarted by the female crabs. I've got 7 in a hatching tank, waiting for them to release their zoeas. There are two or three berried females in the main tank as well, but I have not seen any activity out of them either. Two of the crabs have been holding their eggs for at least 3 weeks in the holding tank; they've got to be about ready to burst.

I rearranged things somewhat, floating my hatching tank in my main crab tank (a 20L). It will keep the crabs' temperatures up about 5-8F compared to ambient room temperature and might give me a bit more luck with the zoeas. This has been the case for a week or so now. The hatching tank also is getting much more light at this point and algae is growing on the walls. There are places for the crabs to hide though, and they seem OK with the confinement.


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## Smokeygrey (Feb 17, 2012)

I read there is a stage where the Zoeas bury themselves in the sediment where they
begin eating organisms in a manner similar to the adults to begin the next stage. Not sure if this is true for this species of crab. But from reading all accounts on breeding micro-crabs and keeping the Zoeas alive, none have tried putting a patch of dirt/fine grain sand in their tanks. Maybe this would be worth a try.


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## jasonpatterson (Apr 15, 2011)

Thanks for the suggestion. At this point I'm just trying to get zoeas still.


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## jasonpatterson (Apr 15, 2011)

This morning I found one of my berried crabs dead, or very nearly so. I removed all of the remaining females to the main tank and tried putting the immobilized crab in a container of clean tank water, but no luck. I don't know why she died, the water tested clean and the other inhabitants were perfectly fine. 

While it was disappointing to lose a crab, particularly a berried female, this gave me an opportunity to try hatching the eggs artificially. I broke out my dissecting microscope and went to work, and I took a few pictures along the way. My camera is nothing special at all, and the pictures were taken by holding it up to an eyepiece, so these are not works of art, but they are instructive. The view through the eyepieces is much better, both wider and clearer.

A dorsal shot of the crab.








These crabs are described as setose or pilose, because they have a number of hairy protrusions called setae. This species in particular is very pilose, thus its genus name Limno (lake) pilos (hairy.) This is a shot of one of the chelipeds. This individual is not particularly setose compared to some that I have, but the setae are very easily seen.









A ventral shot of the crab. The entire yellow portion of the body is actually the tail, curled under the crab's abdomen. Immediately above the tail are two small openings called the gonopores (which I really wish I had gotten a picture of) through which the eggs are deposited on the tail.








Because the animal had been dead for a time, its body was relatively stiff. I tried to get an image of the tail while it was still attached to the body, but couldn't manage to get the camera and tweezers to cooperate. I removed the tail. 









In spite of its appearance as being completely laden with eggs, none of the eggs are actually attached to the tail. Instead of depositing its eggs on normal pleopods, this species appears to attach them to special, feathery protrusions (more setae? very oddly adapted and attached pleopods??) from the edges of the tail. The eggs are attached to the protrusions in groups of 20, with perhaps 10 or so of the protrusions present. Here is an image of one of these feathery protrusions, with eggs and the tail present for comparison. Any eggs not attached directly to the feathery protrusions were directly attached to other eggs.









After removing the eggs, I placed them in a container of tank water and installed an air stone. The eggs are too small to hatch by tumbling, so I intend to keep the water in the tank well aerated and circulating, and to stir the eggs several times daily. The vast majority of the eggs are detached from everything, but 10-20% are in small clumps still. I've got my fingers crossed, both for the eggs and the remaining females that are back in the tank.


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## Smokeygrey (Feb 17, 2012)

Sorry to here about the lost,

Good luck.


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## Omnomshibob (Feb 6, 2012)

Hi there, I've read somewhere that the zoeas are carnivorous from the very start.
I have just moved my first berried female to her own tank that I have been breeding
all kinds of micro-beasties in, also got at least 5 types of phytoplankton. She mated 5 minutes after I introduced her into my regular shrimp tank. The shop didn't put any foliage in with them (6) and when I got home they were all tangled together 
in a ball, didn't seem bothered though, they all dispersed peacefully enough once released.
Anyone know how long it takes from mating to egg release?
They mated exactly a month ago today.


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## aquaponicpaw (Dec 9, 2011)

jasonpatterson said:


> This morning I found one of my berried crabs dead, or very nearly so. I removed all of the remaining females to the main tank and tried putting the immobilized crab in a container of clean tank water, but no luck. I don't know why she died, the water tested clean and the other inhabitants were perfectly fine.
> 
> While it was disappointing to lose a crab, particularly a berried female, this gave me an opportunity to try hatching the eggs artificially. I broke out my dissecting microscope and went to work, and I took a few pictures along the way. My camera is nothing special at all, and the pictures were taken by holding it up to an eyepiece, so these are not works of art, but they are instructive. The view through the eyepieces is much better, both wider and clearer.


Thanks for sharing, Your Pics are some of the best that I've seen out here, Keep them coming.

What temp do you have your Hatchery at? And How many eggs total would you guestimate?


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## jasonpatterson (Apr 15, 2011)

aquaponicpaw said:


> Thanks for sharing, Your Pics are some of the best that I've seen out here, Keep them coming.
> 
> What temp do you have your Hatchery at? And How many eggs total would you guestimate?


The eggs are in a Dip N Pour (roughly 1 quart container) floating in my main shrimp tank. It's at 73 F. There were 100-200 eggs on the crab. They are larger eggs than amano shrimp have, so I'm expecting larger, more developed zoeas from them. That's the general trend with crustaceans, in any case.


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## msjinkzd (May 12, 2007)

fascinating!! I am so glad you are documenting this. I hope you continue to take pictures of your efforts.


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## jasonpatterson (Apr 15, 2011)

The eggs that I was trying to hatch artificially were all devoured by some sort of pest worm about two weeks ago. There was much swearing in the Patterson household the morning I found them out. In happier news, I finally have zoeas in my main tank. I've collected about 20 of them with a pipette and transferred them to a holding tank until I decide what I'm going to do with them exactly.

The first thing I attempted was to see whether they required brackish conditions to develop. I removed 5 of them and transferred them to my amano zoea growth tank. It would appear that they do not need brackish conditions, as all 5 were dead within an hour. That said, it is possible they require a lower salinity than is present in that tank (1.017 at the moment) or an easier transition to brackish water (which would be completely unlike the other species I've been working with that require brackish.)

The remaining zoeas are currently in the Dip N' Pour floating in the main tank, waiting for me to collect more of their brothers and sisters. I've added a tiny amount of 5-50 micron golden pearls as food, as well as some pond/green water that I've been culturing. Hopefully they find something in the mix that they want to eat. 

I took some pictures of one of the zoeas with my dissecting scope. It was alive at the time, and the lighting wasn't great, but there was a lot to see and some of the zoeas behaviors are more clear now, particularly their movement patterns. It was also nice to be able to confirm that this was indeed a crab zoea and not some other sort of zooplankton. I'll post some of the images later today or perhaps tomorrow, along with an update about the routine I'm following.

ETA: Sick kid today, so my day off while she was at preschool became the let's pretend this is the Patterson General Medicine Center day. Hopefully I'll be able to get the pictures going Tuesday, or Wednesday at the latest. I plan on taking pictures each day until the zoeas develop or die (or I see something shiny and lose track.) It does appear that they are eating though, both in the main tank and in my growout container.


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## jasonpatterson (Apr 15, 2011)

Once I had a chance to review the images I've taken of the zoeas, I found them to be pretty poor, to put it delicately. I'm posting what I've got, because even these terrible pictures have something to show, but hopefully I can improve their quality tomorrow and beyond. Some of the observations I'm making here are not readily visible in the images. The quality of the image through the microscope is vastly better than what I've been able to capture thus far. I'm working on improving the image quality, but I also can't afford to spend money on better cameras, optics, and lighting, so I wouldn't get my hopes up if I were you.

*Day 1* (Or possibly later, this is when I saw them in the tank. I suspect it was the morning after they had hatched though.) - 

The zoea has eyes that are still a part of its body, almost eyespots, rather than being at the end of stalks. When they swim, they move very slowly, but will occasionally jerk rapidly in the water. The jerking motion occurs when they extend their tail (curling upward on the right side of the zoea shown below), which is normally tucked into their exoskeleton. It didn't appear clearly in this picture, but the zoeas have spikes both on top of their heads and on their sides, which is a characteristic of crab zoeas in general. The animal is essentially spherical at this point, about 0.1mm in diameter.









*Day 2* - 

The zoea looks much the same in this picture, though it does show signs of change. The coloration is much darker overall and the beginnings of appendages growing from the head are visible. The tail is tucked under the animal's exoskeleton in this image, curling upward on the left side.









*Day 3* - No image. I hope to be able to return and complete the set of development photos at a later date.

*Day 4* - 

Major changes are taking place in the zoea's development. The eyes are now external to the body, at the end of stalks. The gills are also much larger and more active. It's possible to see one of the side spines at the bottom right of the animal as well.

This image is a dorsal view of the animal, rather than the lateral views that came before. I was able to view the earlier zoeas in the same position but did not manage to get any pictures of them while they were turned this way. On earlier days there was almost nothing additional that was visible at this angle. The gills were small and barely visible and the clearish area on the bottom left of the animal in this picture (where I have indicated gills) appeared to be completely empty. 

I apologize for the quality of this image, but believe me, it was far and away the best I took. I really need to improve my lighting for my dissecting scope so that I can compensate for faster moving specimens. I also had my first zoea death, and I'm afraid that it might have been one of the specimens I examined earlier, so I'm trying to be more gentle with them from here on.


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## jasonpatterson (Apr 15, 2011)

General notes on the care I've given them so far - 
The zoeas I have captured are living in a 1/2 gallon container that is floating in a larger aquarium. The temperature is 73 F, lighting is 12 on/12 off. In their container I have placed red root floaters, both because there are reports that the microcrabs develop in the roots of floating plants (water hyacinths are usually mentioned, even though they are not native to the area where microcrabs are from) and to try to help keep ammonia/nitrites/nitrates low. They have been fed a very small amount of 5-50 micron golden pearls, a smaller amount of spirulina, and a large quantity of cultured pond water. The cultured pond water contains a wide range of zooplankton and phytoplankton species. I've been doing small water changes daily. Only 1 zoea has died as of day 4, and I suspect that that may have been due to 'rough' handling in moving it to and from the microscope.

Behavior - 
The zoeas have no interest in the floating plants whatsoever. They spend virtually all of their time at the bottom of the container, moving about slowly. They neither congregate nor avoid one another. They are not attracted to the lights at the top of the tank in any way either. When my next batch of zoeas hatch, I may test whether they burrow, as Smokeygrey suggests. At the moment they appear to be a flock of tiny, grey sheep, aimlessly grazing in a field.


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## msjinkzd (May 12, 2007)

enjoying the updates. I found a TEENy crab in my tank today, about 1/3 the diameter of the smallest I have imported. i am thinking they were born in teh tank, but as I have not been paying close enough attention, there is no way to know for sure.


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## jasonpatterson (Apr 15, 2011)

That's awesome! Congratulations!!!


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## shrimpo (Aug 2, 2009)

This is a great topic, Thank you for taking the time to keep us updated.


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## Smokeygrey (Feb 17, 2012)

Nice update. I really Hope you succeed in this and get it figured out.


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## jasonpatterson (Apr 15, 2011)

Curse you Mother Nature!!! All but two had died by day 5, the remaining two zoeas appear to have died last night. I'll keep my container going for a few days in the hopes that I've missed something, but it looks like this set of zoeas is a wash. 

I examined a couple of dead zoeas, and there really wasn't much to see. I was unable to see a full stomach of food though, so it might just be that they're starving to death. I don't really know what else I could have tried feeding them this time around, as their tank contained a huge variety of potential food sources. I'm planning on scooping up some fresh pond water, filtering out anything bigger than a zoea, adding some clean dirt, and letting it grow until my next batch is ready. At that time, the zoeas will be dumped in and I'll just have to be patient and hope.


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## msjinkzd (May 12, 2007)

here is a pic of the ONE baby I found- I have been seeing it for several weeks now. The ramshorn shell near it is quite small. the white is normal grains of sand and the crab is climbing over a rib to a leaf (for perspective on size)


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## jasonpatterson (Apr 15, 2011)

That's really cool. It's so cute.


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## jasonpatterson (Apr 15, 2011)

I found two zoeas in the main tank, which means that there are likely many more still in there, down in the substrate. Hopefully I'll be able to follow any further developments, but for the time being I'm going to stop capturing them for pictures unless something major develops.


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## somewhatshocked (Aug 8, 2011)

This is the most exciting thread I've read in a while.

I've never had survivors and this gives me fresh hope.

The idea of having this species tank-raised on a larger scale is beyond exciting.


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## jasonpatterson (Apr 15, 2011)

I actually am trying to contact the researcher who discovered the species and has done some work with it's environment and behaviors in the wild. It's a long shot, as he's a busy guy with a major lab to run, but I'm hopeful.


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## wetworks (Jul 22, 2011)

Thanks for posting updates- I am anxious to see you be successful. The pics and very detailed posts are great.


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## jasonpatterson (Apr 15, 2011)

I wrote a message to Dr. Peter Kee Lin Ng, who, with Christina Chuang, first described L. naiyanetri in 1991. He had written a second paper describing their ecology that was behind a subscription wall, so I requested any information about diet, behavior and breeding that he was able to offer. I was delighted to receive a reply today; he's the head of a sizeable crustacean study lab and I hadn't honestly expected him to give me the time of day.

Unfortunately there is a lot left to learn about the habits of microcrabs in the wild, so there wasn't a lot of new information, but he did have some guesses and it was good to be able to pin down some information about these animals as fact. The information that he provided was more focused on the adult animals, and it appears that little is known about the habits of the zoeas.

The following is from his email:
Habitat:
The original specimens were from a large swampy pond, but they are also present in large canals, streams, and other water bodies with slow flow. They are only found in shallow water that is filled with floating vegetation and debris. They do like to live in the roots of water hyacinths, even though it's a non-native plant. They also like to live in the roots of submerged plants. Dr. Ng specifically states that though he has seen aquarists keep them in tanks with plants like hydrilla, he has never found them on green plants in the wild, only on root systems and in debris. He suggests that floating root systems should offer us the best chances to successfully rear the larvae.

Water conditions:
The water that they are found in has moderate levels of oxygen. In general, the waters in the area are neutral to slightly acidic and somewhat hard. (No numerical values were provided.) Dr. Ng suspects that small amounts of salt may be required to rear the larvae, but states that they are not normally collected from bodies of water immediately adjacent to the ocean.
P.K.L. Ng (personal communication, April 20, 2012)

I think my next step is going to be setting up a half 10 with red root floaters and a dirt/leaf litter bottom. I'm going to build a swamp and keep it in my dining room. The wife will be thrilled.


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## msjinkzd (May 12, 2007)

Interesting, I do have a dirt bottom and an infestation of lfoaters in my crab tank.


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## aquaponicpaw (Dec 9, 2011)

Good For you! I admire your effort and dedication. a few questions: These Crabs were first described in 1991. So does that mean that is when they were first discovered ? No one seems to know the true history of these crabs. How long have they been around? are they a hybrid? or did they evolve in some way dictated by the environment? Did they come from the sea and somehow become "land locked"? You look at Asian culture almost every animal is represented in some other form. why not these?


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## msjinkzd (May 12, 2007)

I wanted to share this picture of how the snuggle intothe roots of floating plants. This is a narrow leaf java fern, but it is not attached to anything. I find the most crabs (by the dozens) tightly wedged into their roots.


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## jasonpatterson (Apr 15, 2011)

aquaponicpaw said:


> Good For you! I admire your effort and dedication. a few questions: These Crabs were first described in 1991. So does that mean that is when they were first discovered ? No one seems to know the true history of these crabs. How long have they been around? are they a hybrid? or did they evolve in some way dictated by the environment? Did they come from the sea and somehow become "land locked"? You look at Asian culture almost every animal is represented in some other form. why not these?


These are virtually all wild caught crabs. They were described in 1991, but it seems nearly impossible that they had never been seen previously by locals. They aren't hybrids, and like other freshwater crustaceans, they presumably adapted to freshwater environments over time via a brackish period.


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## jasonpatterson (Apr 15, 2011)

msjinkzd said:


> I wanted to share this picture of how the snuggle intothe roots of floating plants. This is a narrow leaf java fern, but it is not attached to anything. I find the most crabs (by the dozens) tightly wedged into their roots.


I find mine in the roots of my red root floaters, even though they must have had to swim upward 6" or so to get to them. I've never seen them go up, but every morning there are half a dozen crabs hanging on up there.


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## jasonpatterson (Apr 15, 2011)

It's been a bit since I updated this, but I have made some changes to my setup and hopefully that will help. I wanted a dedicated crab tank so that I could feed them appropriately and filter in a way that would not disturb the zoeas. The space that was available only permitted a tank that was 8" tall or so, so I decided to make a half-10 tank. I bought a 10 gallon tank from Petsmart, disassembled it entirely, keeping the bottom plastic frame intact, and cleaned all the glass. The size walls were cut to a bit more than 6" and then I reassembled the tank. The bottom frame and the construction of the tank allowed me to flip the pieces so that my cut edges were downward and any unevenness or differences in height were masked. The final result isn't perfect, but it's not terrible either. I added about 1.5" of topsoil to the tank and filled it up. While it cycled a fair bit of tannins came out of remaining wood chips in the soil, and I figured out a way of doing water changes that doesn't disturb the substrate at all. Again, it's topsoil only, so until it had grown a bacterial mat that fused the surface it was very easy to disturb and cloud up. I also added several maple leaves for cover and extra surface area.

I didn't want any current to speak of in the tank, so I went with an air powered corner filter. I filled the container with biobeads, modified it to use an airstone (which makes it much much quieter) and added an elbow to the outlet to force the water to the side as it exits the filter. As a result the filter is very quiet, produces almost no current, but does a good job in the biological filtration department. 

I bought the double bright LED light from Marineland. I'm not thrilled with it, but it seems to be doing the job, suspended about 4" above the water's surface. The light it provides is in very tight cones, so it acts like a set of spotlights. Apparently the longer fixtures don't have this problem, but the one that fits a 10g definitely does. The only plants I've got are red root floaters, and the roots extend to within an inch or two of the dirt at the bottom of the tank in a few of the larger plants. They're growing, and flowering even, with this lighting, so hopefully it does the job in the long run.

Finding and catching the crabs from my main tank has been the biggest challenge thus far. I've had a population explosion in both my bumblebee and yellow shrimp and they don't leave a lot for the crabs to eat. I've lost 3 or 4 crabs over the last two weeks, far more than in earlier periods. I don't want to disturb the tank too much, so thus far I've only been able to nab 6 of them. It's a mix of 2 males and 4 females so far, and one of the females was berried. She hatched out just this evening, which was really cool to see. She was hanging from the roots of one of the RRF and flapping her tail, spewing out the zoeas into the tank. I'm hoping that the tank is able to support the zoeas, but it's fairly new, so there really isn't much for them to feed on yet. Lots of bacteria and stuff like that. We'll have to see how it goes.


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## Fishfur (Jan 29, 2012)

I'm thrilled to find this thread. I obtained six of these charming little crabs just a short while back, and have already lost one, no idea why. No idea whether it was male or female either. I have seen one feeding in the roots of a water sprite, the others I have not seen at all. There's a large piece of driftwood in the tank, a 5 G, and they seem to hide under it. They are nearly the same colour as the wood. I've been using the tank as a brooder for Ghost shrimp and currently have a number of one/two week old shrimplets in there, plus one Blue Claw Whisker shrimp who is much to canny to catch. 

Moon sand substrate, loads of large frogbits, giant duckweed and water sprite, so lots of hanging roots for them. Been feeding very sparingly, as there is little mechanical filtration. Filters are a sponge, inside corner and small Fluval power unit. Being concerned about shrimp larvae being sucked into filters, I covered the latter two filters with 100 micron filter felt and stitched it on, so it gathers only microscopic detritus on the outer cover for the most part. Thus most of the filtration is biological. I do the odd WC, usually with a air hose stuck in the sponge filter uplift, to avoid sucking up shrimplets. I recently learned there are amphipods in this tank too. Don't really mind, they are kind of cute, and do not seem to be able to catch shrimplets.

So far, I have not been able to observe the crabs enough to have a prayer of sexing them, but I am most anxious to attempt to raise any eggs that may hatch, assuming I have both sexes. I'm going to read the papers that are linked here soon as I finish this. I too was wondering about brackish water for the eggs. While my Ghost shrimp have done fine in FW, my Whiskers have not, and I was going to do a brackish tank for them, in hopes they are similar to amano shrimp. They and the ghost shrimp are certainly breeding well in my 30 G main tank. All my tanks are fairly heavily planted at this time, with either eco complete or moonsand substrates.

Local water is quite hard and tends to a high Ph, close to 8 as it leaves the tap. I use mainly conditioned tap water, and so far, everybody seems quite happy, but the crabs are in the small brood tank, which tends to become more acidic with time and because I do fewer WCs. I think likely the big piece of wood in a small volume of water is doing the acidifying.I top up with distilled water, but I do WC with tap. The shrimp so far seem not to care about some fluctuations in their conditions, but I worry about the crabs. I have another tank ready to go, also 5 G, no fish, but it also with a few amphipods.

I have been feeding an assortment of sinking crustacean pellets, algae tabs, liquid invert food, meant for corals, green water and finely powdered spirulina mixed in water, mainly to feed the free swimming larval stages for the Ghosts. I feed those last three to my clams as well. There are snails in all the tanks.. pond, mystery, horned and zebra nerites. I thought it might be fun to try hatching some nerites in a brackish tank too, though to date I have zero experience with salt water of any kind.

If anyone on here has any suggestions on what conditions I should aim for in my new crab tank, please let me know. However, since it is difficult to fight the way the local water likes to be, and I am not in a position to afford RO water, I am hoping they are able to adapt to what I've got. I have a small distiller, gives me a gallon a day when I run it, but it's not enough to keep a tank going non stop without any tap water being used. Could maybe do half and half if need be. I do use it for top ups to avoid making the water any harder than it already is.

Any and all suggestions most welcome. I would be beyond ecstatic to succeed in breeding crabs. Just having the Ghost shrimp morph and survive was a huge thrill as I am quite new to shrimp keeping too. I later found better than half a dozen Ghost shrimp survived in my 30 G tank as well, despite the hazards of the filter, the pump, the danios, kuhlie loaches and three dozen odd shrimp that are also in there. Filtration may not be as big a hazard as I feared it might be, but I'd still make every effort to prevent any eggs or larvae from accidentally being sucked in. There is even 55 micron felt available to make filter covers with. In my main tank, all I did was make sure to stuff some intake grates with coarse sponge cut to fit, to prevent baby shrimp from getting sucked in, but I didn't cover the slots on the lid, only the ones at the front and lower edge. I must confess that the half dozen survivor Ghosts are likely all that's left out of, probably close to one hundred eggs that were let go in there, so it's not a great rate, but I was amazed that any managed to live. 

Also, any suggestions on how to actually see my crabs without stressing them too much. They've been in their tank only for a week, so I hate to bother them just yet, but I want to see if I can discern the sexes and also whether they're eating. Would simply raising the piece of wood onto a couple of small rocks be likely to help me see them without taking away their hiding places ? There are no rocks to speak of in this tank, just the sponge filters and the big driftwood piece that goes from the front to rear corner on the diagnonal. Has a lot of ferns tied to it and some mosses, but not much has had a chance to become solidly attached.


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## jasonpatterson (Apr 15, 2011)

Best of luck raising the larvae. There's something missing that nobody has quite figured out yet. 

My crabs became a little less shy over time, but with a good sized piece of driftwood, you're not likely to get all of them out. Feeding something like bloodworms or mysis shrimp can lure them out, especially if you do it right before lights out and watch closely afterward. They are quite shy though, so there's not a lot you can do. You might be able to use rocks to lift it up, but they'll climb under the rocks as well.

Sexing the crabs is fairly easy once you get a look at them. The males have a tail that is shaped like a v, and the females have a tail that is shaped like a broad U. If the tail is yellow, the crab is berried.


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## jasonpatterson (Apr 15, 2011)

An update on my current batch of zoeas:
I had a second berried crab that hatched out as well, and a swarm of zoeas to accompany the event. After about an hour, neither batch of zoeas was visible. I know that when I kept them in a small container they went straight to the bottom and stayed there. In this tank there is a lot of cover for them on the bottom, and they may be burrowing as well. I haven't seen a single zoea from either batch since almost immediately after hatching. It's frustrating, because there's really no way to know whether what I'm doing is working without seeing a baby crab some day.

I really don't expect the current lot of zoeas to live anyway, as the tank is awfully new and there isn't a lot of microflora/fauna in the tank.


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## dougolasjr (Mar 3, 2010)

Any update?


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## jasonpatterson (Apr 15, 2011)

Complete and utter failure on all fronts thus far. I'm moving in the next year or so, so I'm trying to avoid getting anything new during that time. I've been losing a crab now and again as time goes by, and my population is dwindling. I'm going to give it another serious go once we move, if all goes as planned.


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## dougolasjr (Mar 3, 2010)

Well that's unfortunate. I was hoping to hear good news.


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## DannyDapper (Oct 12, 2012)

Any updates on your attempts to breed them?


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## MABJ (Mar 30, 2012)

jasonpatterson said:


> Complete and utter failure on all fronts thus far. I'm moving in the next year or so, so I'm trying to avoid getting anything new during that time. I've been losing a crab now and again as time goes by, and my population is dwindling. I'm going to give it another serious go once we move, if all goes as planned.


I was happy to see this thread. 

I've read everything I can online about them. The best I've gleaned from advanced German breeders is that they found some correlation between light and survival. Also being that they're filter feeding, I'm sure a food has something to do about it.

So my assumption... Which may be a stretch.. Is that light is their orienting factor. They stay close to the surface to (in their home river) get a micro algae or micro particle of food which they catch as they move down the river quickly. We have yet to be able to replicate this unfortunately. 

Nobody has been able to bring them past day 9. Other than miracle baby by Rachel? That's an anomaly I've never heard of. It only takes a few days for them to grow out of their free floating form, like your amazing pictures documented. 


MABJ's iDevice used for this message


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## blacksheep998 (Jan 16, 2011)

MABJ said:


> I've read everything I can online about them. The best I've gleaned from advanced German breeders is that they found some correlation between light and survival. Also being that they're filter feeding, I'm sure a food has something to do about it.
> 
> So my assumption... Which may be a stretch.. Is that light is their orienting factor. They stay close to the surface to (in their home river) get a micro algae or micro particle of food which they catch as they move down the river quickly. We have yet to be able to replicate this unfortunately.


Probably a stupid question but has anyone attempted raising the babies in green water?

I'm not sure how to replicate the water flow, but maybe if they're literally swimming in food they'll be able to survive.


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## MABJ (Mar 30, 2012)

blacksheep998 said:


> Probably a stupid question but has anyone attempted raising the babies in green water?
> 
> I'm not sure how to replicate the water flow, but maybe if they're literally swimming in food they'll be able to survive.


Yes. Rachel attempted, I believe, to raise several larvae in green water. I'm pretty sure she had one stray baby make it but that was in her normal tank. So I don't know what miracle happened there. 

Trust me I don't know the answers either. Otherwise I'd be making a killing off breeding and selling these guys. 


MABJ's iDevice used for this message


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## Cokers (Aug 15, 2011)

It has been a year and 2 months, I'm assuming you gave up?


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## wootlaws (Feb 25, 2011)

Nice pics and thanks for the documentation


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## Raymond S. (Dec 29, 2012)

Don't know where you would look for one of thes but while I collected reptiles I 
had maps showing where they live(in the U.S.) an presume a similar map exist for these critters. Don't know that in clams their called that but the zoeas of clems need to attatch themselves to fish for the x amount of their life.
The map(s) may indicate if the brackish water thing might apply. And I absolutely believe that algae is essential to their survival.
In a thread about Banded Pigmy sunfish, one sucessful breeder on here has Riccia
in their tank and says the babies are always in it. Floating I might add. And these babies start out just a tad bigger than microscopic.
I'm interested in these crabs but that no money at the end of the month syndrome is uppon me mostly from a combination of cigarette smoking and a rent increase that
put me less than having extra funds always there. So priorities do prevail.
Just passing on a couple of my thoughts on these facinating little critters.


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## dougolasjr (Mar 3, 2010)

Rachel posted a picture of young Crabs latched on to the mother crab so all the accounts of them being released may have been early failures. She has an article on it.

http://www.reef2rainforest.com/2014/03/20/thai-micro-crab-limnopilos-naiyanetri-new-breeding-progress/


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## alcimedes (Dec 7, 2014)

Wondering if there are any more current updates to people breeding micro crabs? I'm tempted to order some for our office planted tank, but I'd like to know if people have been able to successfully breed them at all yet or not.


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## jasonpatterson (Apr 15, 2011)

The only person I've seen any sort of success from is Rachel (msjinkzd). She reported that her crabs bred when fed powdered food and given some current at the top of the tank. The moms hold onto the babies after they hatch until they mature. 

We were getting lots of zoea and not realizing that they were essentially miscarriages. I wouldn't rely on them to breed, but it's not impossible.


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## vinnyvidivici92 (Apr 22, 2017)

I'm probably a bit late on this discussion, but micro crabs will attack shrimplets if given the opportunity. 
I watched one of mine trap a shrimplet in the gravel so it couldn't escape and grabbed him and pulled him out of the rocks nxt to the glass and tried to eat him so I scared him with a bamboo skewer and alas the shimpy was still alive and recovered shortly after


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