# Dwarf Crayfish and Cherry Shrimp Mysteries



## Natty (Apr 2, 2008)

Okay, I've had a few threads, but I really need to find a solution. Can someone help me work it out and narrow it down?

CRAYFISH PROBLEM
Alright, I have dwarf crayfish in a 10 gallon. There's about 6 adults in there.

Well, I've not have much success in keeping the babies in there, they just seem to disappear. They hatch and I see them, but they disappear after a day or two. The adults live in there perfectly, they seem perfectly okay and active.

However, after awhile I got tired of it so I sucked the babies out and put them in a seperate container that floated in another tank. The babies survived! I feed them crab cuisine.


So I've come up with a few deductions. Please help me this has been going on for months and it sucks.

1. Can't be air problem, I definately know for sure it isn't the issue. They have enough oxygen.


2. The water params seem great. In the crayfish tank where the adults are, it is 0-0-0 across the board. I understand it since the top has a lot of wisteria and....there's only 6 dwarf crays, I mean how much mess can they create? Not much.

3. I don't overfeed, I just feed enough that the food is gone in a few hours.



So my guess is it is either because:

1. The adults are snacking on them, which confuses me because I got 3 large lava rocks in there including the mass of plants at the top and I only got 6 adults in there. I mean, the babies dodge out of the way really fast when the adults come, I just dont see how they can all be caught so fast?

2. Something I'm feeding them? I've only fed them crab cuisine and the babies that I seperated into a completely different container with normal nonRO filtered water, I've also fed them the same and they are alive so can it be the food? My friend said that even a little bit of copper can kill babies because they're weaker. He doesn't like crab and lobster bites because he said there's copper in there but I don't see it anywhere in the ingredients. Are there any foods that you guys dont trust?

3. Copper in my piping. But if that's so, why are my cherries still alive, why are the adult crayfish still alive. My cherry numbers are not increasing much as well.



What I'm going to do:
I'm going to test the water inside the adult crayfish tank by making a seperate container and poking tiny little holes in it and floating it inside. So if it is the water, they'll still die. If they don't die, then I know it isn't the water and it is the adults.

What you guys think?


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CHERRY SHRIMP PROBLEM
Okay, I use the same water here and my cherry shrimp numbers aren't increasing much, they stay around the same and that confuses me.

However, my issue is this:

I have a crayfish tank, different dwarf crayfish species and different tank from the crayfish tank I talked about above. It has AS in it, been there for months. Well, the crayfish in there are eating and living normally and I got some java fern trident and lots of floaters in there. However, I've added some cherries into the tank and they all manage to disappear.

So...what gives? If the crays are doing great, how come the cherries just disappear? Either the dwarf crays are hunting them down or something. 

I'll add the params later when I do a test but it should be good. I'm completely out of ideas. Well, I got some ideas but I've been putting it off. I think im going to try that container thing. If it is the water, they'll die even when in the container completely seperate from the crays. If they survive, I guess it's the crayfish then?


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## FrostyNYC (Nov 5, 2007)

Well, if you suspect the dwarf crays are eating their young, I wouldnt be surprised if they're eating RCS.

Another possibility is your filtration. Are you sure they're not getting sucked into the inflow?


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## epicfish (Sep 11, 2006)

Crays are cannibalistic. They'll eat their babies. And the babies will eat each other. They'll eat shrimp too. It first starts with a snipped antenna or two then you'll see the shrimp population stay relatively constant as the shrimp breed while some are attacked by the crays.


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## Natty (Apr 2, 2008)

FrostyNYC said:


> Well, if you suspect the dwarf crays are eating their young, I wouldnt be surprised if they're eating RCS.
> 
> Another possibility is your filtration. Are you sure they're not getting sucked into the inflow?


No I've had shrimps way too long, I've always used sponge over the intake.



> Crays are cannibalistic. They'll eat their babies. And the babies will eat each other. They'll eat shrimp too. It first starts with a snipped antenna or two then you'll see the shrimp population stay relatively constant as the shrimp breed while some are attacked by the crays.


I've always been told that dwarf crays are very nice and won't. Can we actually say that they're aggressive and will actually hunt down similar sized creatures such as dwarf shrimps and eat them?

Also, if I do seperate the babies, at what size can I reintroduce them back safely with the parents and better yet, how do I keep the babies in there with the adults and not have to seperate them? Seperating the babies isn't exactly easy, they just don't all line up to be saved or anything like that .


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## epicfish (Sep 11, 2006)

Natty said:


> No I've had shrimps way too long, I've always used sponge over the intake.
> 
> 
> 
> ...


I doubt you can cram in more than six adults without having them fight and risk losing one or two. That's the nature of the beast. I used to keep around six pairs in a 10g tank but I would be trying to re-home at least three pairs in the meanwhile.


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## Natty (Apr 2, 2008)

epicfish said:


> I doubt you can cram in more than six adults without having them fight and risk losing one or two. That's the nature of the beast. I used to keep around six pairs in a 10g tank but I would be trying to re-home at least three pairs in the meanwhile.


 
Well, I've fitted more into the tank without much issue. They find each other and fight anyway but they get away fairly easy.

I just didnt know they're able to catch those tiny babies, they don't look like they're anywhere fast enough to do that....


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## epicfish (Sep 11, 2006)

Natty said:


> Well, I've fitted more into the tank without much issue. They find each other and fight anyway but they get away fairly easy.


Until one attacks another one just after a molt.


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## Natty (Apr 2, 2008)

epicfish said:


> Until one attacks another one just after a molt.


Don't they flick their tails even during molts to get away? I've seen them do that a few times.


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## epicfish (Sep 11, 2006)

Natty said:


> Don't they flick their tails even during molts to get away? I've seen them do that a few times.


I've seen two fighting with each other, wrestling with their claws, pretty much when a larger, third one came up behind of the the first two. SNIP SNIP. There goes two legs. Hahahahah. Crazy crays. Grew them back though.

I have lengths of PVC (spray-painted black to match my substrate) with moss glued (hot glue gun) to the inside of them as hiding spots for the cray. My 10g has six or seven 4-5" lengths. Helps them from fighting and gives them places to hide once they've molted. Cut down on fighting and missing limbs. Would be an idea if you're trying to breed them.


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## Natty (Apr 2, 2008)

I just can't really comprehend how the babies are getting captured by the much slower adults. It's hard to build anything if I don't fully understand what they're capable of. What kinda paint spray did you use that won't leak toxins? 

I don't have a power saw to cut through it either, wish I did.....that's a nifty idea though. Buy a bunch of 2" or so diameter PVC and poke holes around the middle end as well.

But yeah, I don't see how the adults capture the babies. If they're that damn good at catching the babies, then it might just be useless. The babies dodge away so quickly though....


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## epicfish (Sep 11, 2006)

Natty said:


> I just can't really comprehend how the babies are getting captured by the much slower adults. It's hard to build anything if I don't fully understand what they're capable of. What kinda paint spray did you use that won't leak toxins?
> 
> I don't have a power saw to cut through it either, wish I did.....that's a nifty idea though. Buy a bunch of 2" or so diameter PVC and poke holes around the middle end as well.
> 
> But yeah, I don't see how the adults capture the babies. If they're that damn good at catching the babies, then it might just be useless. The babies dodge away so quickly though....



Use PVC cutter to cut your lengths.

You've never seen babies dismembering each other?


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## Natty (Apr 2, 2008)

epicfish said:


> Use PVC cutter to cut your lengths.
> 
> You've never seen babies dismembering each other?


It can't be the babies because (referring back to the first post) remember I said that I seperated all the babies and put them into one container?

I had like 13 of them in there. I still have 9 so I think most of the deaths are more due to the adults. Also take note this container is about a hand's length (not arm), so it's about 5-6" long and 3-4" wide only. They're still in there kicking. No filtration, no air, but they dont seem to have problems. However, I have released a few babies a few weeks after in there, they didn't survive. So my guess is, the larger ones are picking the smaller ones. But I don't see how the much slower adults get the tiny babies, that's one thing I don't see happening easily.

I mean the babies were literally wiped out in a week max. All of them, most in 1-2 days. Are the parents that effective in catching their own babies? Crazy....

PVC cutter? Is that like a saw or something and does it make it a lot easier? I tried cutting pvc with a nonpower saw before and it took a long time.

What's the smallest diameter pvc tubing you can get at home depot? I'm gonna check it out though. Thanks for the idea epic and glad you're back!

Oh yeah, how long will I have to wait to reintroduce the babies back in with the adults? Long enough for it to be relatively safe?


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## epicfish (Sep 11, 2006)

Natty said:


> It can't be the babies because (referring back to the first post) remember I said that I seperated all the babies and put them into one container?
> 
> I had like 13 of them in there. I still have 9 so I think most of the deaths are more due to the adults. Also take note this container is about a hand's length (not arm), so it's about 5-6" long and 3-4" wide only. They're still in there kicking. No filtration, no air, but they dont seem to have problems. However, I have released a few babies a few weeks after in there, they didn't survive. So my guess is, the larger ones are picking the smaller ones. But I don't see how the much slower adults get the tiny babies, that's one thing I don't see happening easily.
> 
> ...


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## Natty (Apr 2, 2008)

what do u do if its a bigger diameter pvc? Go saw? What's the max pvc diameter that can be used for?


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## epicfish (Sep 11, 2006)

Ones at HD are up to ~2" or so. I've seen ones up to 4", but those are for industrial use.


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## Natty (Apr 2, 2008)

I guess I have to call them and ask how much is 2" diameter pvc. 

What do you think would work better, a tank full of hornworts or a tank full of pvc piping?



Oh yeah, I've had a few occasions where the adults were looking not that great and I took them out and put them into filtered water in a completely seperate container and they got better. I wonder what's with that?

It just leads me to a different conclusion that whatever got the adults might have gotten the babies as well. It is rare though, but hapens every few months, 1-3 months, one at a time.


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## Natty (Apr 2, 2008)

Hey, I got a bunch of 1 1/4" pvc, is this good and safe for the shrimps? I'm just double checking since I'm fairly paranoid as it is.


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## epicfish (Sep 11, 2006)

It's fine. Make sure it's clean.

Then spray paint it with Krylon fusion.


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## Natty (Apr 2, 2008)

epicfish said:


> It's fine. Make sure it's clean.
> 
> Then spray paint it with Krylon fusion.


K, thanks!


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## skratikans (May 23, 2008)

let us know how that works out
I separate the babies from the adults and raise them for about one month before re-introducing them back


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## Natty (Apr 2, 2008)

skratikans said:


> let us know how that works out
> I separate the babies from the adults and raise them for about one month before re-introducing them back


Something weird happened. I think if you seperate the babies, you have to keep the temperature relatively warm. I placed them into filtered water with a bit of dechlorinator at around 50F, they started to perish gradually. However, I reacted fast and put them back into warmer water and they seem a lot better.

So temperature seems to be an important factor to newborns. After a few molts they become almost as hardy as the parents. An ideal temperature around 68-75F~~ seems to do them good.


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## Natty (Apr 2, 2008)

Heads up, I think now I'm more certain that dwarf crayfish are aggressive predators. On the question about cherry shrimps on the first page, I brought up how my cherry shrimps disappeared in my crayfish tank after a few days.

I only have 3 crays in there. Well, after putting them in a container with holes to seperate the cherry shrimps from the crays but keep them in the same water, all the cherry shrimps remain alive.

So I believe dwarf crays are active hunting predators that will seek out live prey, even those as quick as cherry shrimps. I don't know about all, but from my experience, that's what I see.


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