# Raising daphnia with floating plants



## mistergreen (Dec 9, 2006)

I have a different idea on raising daphnia. 

I brought in water hyacinth and lettuce from the pond in for the winter. I'm putting them in the basement in my spare 39G tank with old aquarium water. I thought to myself, "Why not raise daphnia in there?" The plants will soak up any ammonia and provide O2 for the daphnia. Sounds good?

The daphnia should be very happy in there.


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## mistergreen (Dec 9, 2006)

I did a little more reading on Daphnia Magna. Did not know that they are sensitive to K, Mg, P and some other salts we regularly put in our planted tank.. I hope this will work out for me. The Floating plants should soak up the excess nutrients.


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## hydrophyte (Mar 1, 2009)

Hey what are you raising them for?


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## Wasserpest (Jun 12, 2003)

Let us know how it works out. I am planning to use one of my garage holding tanks to rear daphnia, or cyclops, or whatever will grow in there. :hihi:

What are you going to feed them? I heard bakers yeast is an option.

Some of these crustaceans do very well in fertilizer loaded ponds (drainage collection ponds in fields etc) so they can handle salts and stuff well. Maybe D. magna is a bit of an exception.


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## invert1 (Jun 25, 2008)

Daphnia are super easy. One really cheap feeding method is to get Spirulina from the health food store. I say cheap because like 1 oz lasted me ~9 months on a 10G tank of daphnia, so even though the spirulina is expensive itself it's great to feed them right before you feed the daphnia to your fish b/c then you're also providing color-enhancement in the daphnia.

Also, w/ the spirulina once you get the hang of it, it's a lot easier to make sure you don't overfeed b/c unlike the baker's yeast it's a very clear gradation of color btwn too little and too much.

Also, I'd say if you can find Daphnia magna locally, those are the best species to raise b/c babies can be fed to small fry while the adults are both large and exciting prey for small/med fish and a good vehicle for nutritious food (the spirulina) in significant quantities.


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## mistergreen (Dec 9, 2006)

hydrophyte said:


> Hey what are you raising them for?


they're food for the fishies.

Here's where I got info on d. magna.
http://www.caudata.org/daphnia/

Daphnia living in dirty water or nutrient rich water is a myth. They're often used to test water quality. They'll eat floating algae, bacteria, fungi, and to a lesser extent small vegetable matter (soy, rice flour). The trick is to feed daily but not over feeding. Ammonia, low O2 , chlorine, heavy metals, and high salts will wipe them out. So, I'm thinking floating plants are great buffers.


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## mistergreen (Dec 9, 2006)

I got the daphnia through the mail today from here http://www.aquaculturestore.com. Nice place to get native fish too btw..

Holy cow, d. magna are huge!
I'll admit, it was a little expensive but the culture is clean and healthy. And I don't have to deal with jerks on aquabid.


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## bulrush (May 7, 2007)

I've tried daphnia before. Daphnia are filter feeders. They are unable to pursue food particles because they randomly "jerk" around, and so many food particles must be floating in the water for them to bump into. They will not do well in still water or tanks with right angles, which is why it is common to use a round trash barrel (clean, 4g or bigger) to raise them, and keep water slowly moving in it.


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## SearunSimpson (Jun 5, 2007)

I've written many times on this forum about the rearing and harvesting of daphnia on a hobby sized scale, and one thing I will mention again, is that daphnia are a great food for gut-loading. You can feed your daphnia spirulina, paprika, yeast, and if you can find it, organic dehydrated vegetable powder (pretty much, powdered V8 juice or the sort).

One thing I do suggest though, is that you pre-mix your powders in a little cup of water, or an old yoghurt container and then pour it evenly around the tank, SLOWLY using your hand or something to slightly 'mix' the water so that it gets evenly distributed throughout the water column. 

It is VERY easy to overfeed daphnia, and if you've never kept them, don't be surprised if you accidently kill them all off. They seam to almost peak in population in their given body of water and then there seams to be a huge die-off. To prevent this, collect/cull your population frequently. Not all the way down to nothing, but at least once a week take a good sized scoop out and feed them to your fish.

Also, for this reason, it is also HIGHLY recommended that you keep two cultures going, in case one does happen to die off.

Other than that, they are ridics easy to keep and culture. Just do water changes with old aquarium water, and have slight aeration. 

NOTE: slight areation does not mean a filter. It means an airstone set so that it bubbles with big bubbles and goes 'glop..........glop.........glop'. DO NOT have your airstone fizzing. The tiny bubbles can get caught up under the carapace, causing the daphnia to get trapped at the surface. 

But since you said you'll have those wysteria or whatever, then you might not even need an airstone anyways.


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## mistergreen (Dec 9, 2006)

things are going well. I have no airstone..
My food mixture is made up of spirulina, gluten free flour (a bunch of legumes), and a few pinches of yeast. I mix 1/4 a teaspoon of the dry mix in a little jar of tank water before feeding. I tried straight powder in the tank and it doesn't work. They clump mostly.

The daphnia just started to molt. Hopefully that's a signal for them to start producing eggs and giving birth!


They're pretty fun to watch. They could be the next cool thing to have. I'll start developing S+++ grade daphnia.

Oh, you can't have the floating plants cover the entire tank. They will swim toward light. I like to have all of the floaters to the sides and it's clear in the middle.


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## mistergreen (Dec 9, 2006)

here's a picture of the daphnia when they arrived. Since then, they're taken on a tan color. I guess the food I'm feeding them is giving them that color. You can see this guy's gut.









And I found a few mosquito larvae in the tank. Try to net them out.The big one snagged a baby daphnia or maybe a copepod. Plus I wouldn't want mosquitos in the house. I fed the little sucker to the fish.


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## mistergreen (Dec 9, 2006)

latest pictures... this is 7 days later.


























So these pictures cleared up a few things which the naked eye can't. Their color is around their gut. And they're all pregnant! (eggs on their backs) Lets make some clones!


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## rasbora (Sep 1, 2006)

Interesting stuff, I wonder if you'll notice improved color in your fish after feeding with these for a while.


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## Cmeister (Jul 5, 2009)

Keep us posted


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## mistergreen (Dec 9, 2006)

Lots of babies swimming around now. I read they can start producing offsprings within 4 days. I have to say, these guys are pretty fun to raise. I also added a handful of crushed coral in the tank to adjust the ph and calcium.

I'm getting unexpected copepods in with the daphnia culture as well. More food for the fishes.


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## mistergreen (Dec 9, 2006)

Some babies.
These are a few days old. The new borns are half this size.









I was hoping to get pictures developing youngs inside the mother but I got a picture of clear eggs instead.


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## Cmeister (Jul 5, 2009)

lol they look like little pac-men


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## Twimbo (Oct 10, 2009)

How is the water lettuce doing?

I asked about it at the LFS today and they told me they only stock it in summer for ponds, because its very hard to keep indoors. They said they have tried and failed, as has their supplier.

I was thinking about trying water lettuce as a floating plant, but am now reconsidering.


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## mistergreen (Dec 9, 2006)

they're doing good. You need to give it lights and nutrient tis all.
They are pretty big and grow tremendously fast. If you have any other plants in the tank, they might suffer.

you might want frogbit.


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## mistergreen (Dec 9, 2006)

There was a huge explosion of babies today. I'd say the population tripled to 300.

So the very first day I introduced them into the tank (10-15-09) to today (10-28-09) yielded this much.
I hear their population growth is logarithmic. I should be have a harvestable culture in a few weeks.


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## Wasserpest (Jun 12, 2003)

What do you use for water circulation? How about temperature? Room temps?


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## anastasisariel (Oct 4, 2009)

Not to invade your post but I just wanted to second your recommendation for Paul Sach's aquaculture store. He's a great guy to talk to also and loves to talk native fish. He has the most diverse selection of captive breed native fish that I have seen.


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## mistergreen (Dec 9, 2006)

Wasserpest said:


> What do you use for water circulation? How about temperature? Room temps?


No circulation beside stirring with a spoon at feeding time. It's a 29G tank. I can't see burping bubbles will add all that much circulation. The tank is in the basement at a constant temperature of 72F. They seem to like this temperature, they're very active.



anastasisariel said:


> Not to invade your post but I just wanted to second your recommendation for Paul Sach's aquaculture store. He's a great guy to talk to also and loves to talk native fish. He has the most diverse selection of captive breed native fish that I have seen.


Yes, he has a great collection of natives.


Update on the daphnia:
It is 11-11-09
The Babies from the growth explosion a week and a half ago are now adults. The population is slightly more with babies about 1/4 of the population. No huge explosion yet. I'm guessing another explosion will occur every 2 weeks. Hopefully, the population will be 1000+ by the end of this week.


Maintenance tip:
Every 2 weeks, sometimes every week I change out 5 gallons of water. It's when I do my water change on my community tank. The water from the community tank goes straight into the daphnia tank via a python. Yes, life is hard.

While the lights are on, the daphnia swim to the top which will give you a perfect chance to siphon the organic mulm in the bottom. You will siphon out a small number of daphnia. I mind losing them right now so I siphon into a bucket. Leave the mulm to settle under a light source. Any daphnia will swim to the top where they can be netted.


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## sewingalot (Oct 12, 2008)

mistergreen said:


> Maintenance tip:
> Every 2 weeks, sometimes every week I change out 5 gallons of water. It's when I do my water change on my community tank. The water from the community tank goes straight into the daphnia tank via a python. Yes, life is hard.
> 
> While the lights are on, the daphnia swim to the top which will give you a perfect chance to siphon the organic mulm in the bottom. You will siphon out a small number of daphnia. I mind losing them right now so I siphon into a bucket. Leave the mulm to settle under a light source. Any daphnia will swim to the top where they can be netted.


roud: You just gave me a great tip for cleaning out my brine shrimp tank and not loosing babies.


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## mistergreen (Dec 9, 2006)

It is 11-13-09.

The population doubled, half being babies. I'd say the population is close to 1000 from the original 100.


I bought 3 spoons of live black worms ($3) a few days ago from a lfs. They're pretty easy to keep and breed! I'm surprised more people don't do it. I've always heard about the horrible smells, them dying off easily and you have to keep them in the fridge (ewww, not next to my cold cuts for sure). But that's not the case at all.

They are in a bucket in the basement (72F) in 1/4 -1/2 inch of aquarium water from the daphnia tank. The worms can go into the daphnia tank actually but I'll hold that experiment off ( it would be a pain to catch the worms  ). The water is changed out everyday. It takes a few minutes, not a big deal at all. And they're fed a few tiny bits of algae wafers. I don't think they eat the wafer but rather the fauna that feeds off the wafer. The water from the daphnia tank provides lots of micro-fauna.

I can tell they're reproducing already by the little bits of worms. They can sexually reproduce but they prefer splitting into little bits. So I'm thinking I can feed blackworms once a week. Not too bad. Saves me gas money from driving to the lfs.


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## mistergreen (Dec 9, 2006)

I had another population growth. I thought it would be fun to graph it out. The population is merely guess work. I should learn how to do population analysis.










and boy, they can filter the water. The current population will clear up hazy water in hours.


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## anastasisariel (Oct 4, 2009)

Did you put brown bags or cardboard in with the Blackworms?


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## mistergreen (Dec 9, 2006)

anastasisariel said:


> Did you put brown bags or cardboard in with the Blackworms?


no, didn't bother. They do clump up but you can loosen the clumps up by shaking the bucket. I haven't seen any deaths yet since I bought them last week.


***
Just did a little reading on blackworms. When I would shake the bucket, I must have broken some the worms up a little to make new worms. You can also take a plastic fork and 'rake' the worms to break them up. Reproduction is never easier.


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## mistergreen (Dec 9, 2006)

Last comment on the blackworms: they eat the same stuff as the daphnia, so I had the idea to feed the spirulina mixture I made to the worms. I think this is better than fish food since it's nutritious and microscopic. I'll start a new thread on blackworms if this turns out well.

But in all honesty, they don't grow all that fast. If you have a lot of fish to feed, I'd just buy them instead of trying to raise them.


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## mistergreen (Dec 9, 2006)

I saw a decline in the population. The mulm was considerable. I guess I over fed because of the growing population. I tested the NH4 with my un-calibrated kit. It registered .5-1ppm.


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## mistergreen (Dec 9, 2006)

having fun with population sampling. I got the daphnia to congregate to the side of the tank.










on average, there are 35.4545 in each square. It's a 9x11 grid. Multiply them together, there are about 3,510 daphnia.


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## sewingalot (Oct 12, 2008)

These are much bigger than I would have ever imagined. I know you blew this up, but still. Have you fed any to your fish yet?


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## mistergreen (Dec 9, 2006)

yeah, they're pretty big. The biggest ones are the adults on the top right in the picture, maybe .5-.8 centimeter.

I haven't had the heart to harvest them yet. I'm waiting for them to be around 5000 but the population might be leveling off at 3000. We'll see.


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## mistergreen (Dec 9, 2006)

They seem to love water changes like shrimps. They molt pretty much right after. 
They not only grow but from what I've read, they're ready to reproduce after a molt as well. So, I guess that's key for fast production.


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## SearunSimpson (Jun 5, 2007)

Be careful of the population crashing. If I were you, I'd set up a small 10gl or something, and have a secondary population.
Daphnia are notorious for having crashes. They will peak in population, and hang for a bit, then the next day, they crash leaving you with very few to start all over again.
This comes from the books, and through experience.

Just a heads up. This is why I said in an earlier post to harvest a net full once a week or so. Or, each day, instead of a net full, just one swipe with the net.


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## mistergreen (Dec 9, 2006)

I wonder what causes the crash. It would be interesting if I experience it so I can document it.

In terms of space, the 29G is very spacious.


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## mistergreen (Dec 9, 2006)

this is a quote from Cornel's science department.


> ...under the best of conditions Daphnia populations occasionally crash for no apparent reason.


great.


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## SearunSimpson (Jun 5, 2007)

Yup, thats exactly what I was talking about, lol. I have no idea why it happens, but have experienced it myself. I've never had a population completely die off though, but rather was left with very few (under 100) to start all over again. This is why it may be a good idea to have a secondary population. 
Even though I'm sure you have an amazing set up for them, and they are in great conditions, they very well may one day just 'disappear' .


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## mistergreen (Dec 9, 2006)

I had a little explosion of baby daphnia and decided to harvest the the adults. I think I netted out 100 of them,

The fishes went loco for the daphnia. And they enjoyed the hunt for those that escaped.


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## lauraleellbp (Feb 3, 2008)

Did you decide not to dose ferts on this tank?


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## mistergreen (Dec 9, 2006)

No dosing on this tank. The plants are fine and only show minor deficiency like smaller leaves. All the nutrients are from whatever is in my main tank and the food I'm supplying the daphnia and other animals in the tank.

From the publications, daphinas are sensitive to new water so old tank water works fine.


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## mistergreen (Dec 9, 2006)

Oh and just wanted to note that daphnia are not aimless filter feeders. I've noticed they often graze the tank's bottom if there is nothing in the water column.

Seems like they have other sensory organs besides the eye, perhaps a sense of smell somewhere.


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## SearunSimpson (Jun 5, 2007)

I have noticed too, that after I feed my fish my daphnia, that my fish colour up intensely. I sometimes feed a good scoop before I have company over so that my fish are coloured up nicely for people who may view my tank(s).

One other thing, is that I've noticed that after feeding daphnia is that breeding and mating drives are more intense within my smaller fish (tetras, whiteclouds, etc), with multiple males sparring and driving females into plants.

In the summer, if you still have them, which I'm sure you will, start a small culture outside in a bucket of some sort. You'll get mosquito larvae, and then into the fall you'll get chronomids (midge larvae) and bloodworms.


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## mistergreen (Dec 9, 2006)

SearunSimpson said:


> In the summer, if you still have them, which I'm sure you will, start a small culture outside in a bucket of some sort. You'll get mosquito larvae, and then into the fall you'll get chronomids (midge larvae) and bloodworms.


I've read D. Magna don't do so well in the summer heat. Their optimal temperature is in the low 70's. So spring and fall are good for them.

I do see a few midge fly in late fall but no larvae, definitely no bloodworms. I'm in a city so maybe it's not as prevalent.

Oh, I found a way to get a high density of mosquito larvae. You need to add soil and floating plants in the water and if it goes anaerobic, the better. In a gallon of water, I can net out hundreds.


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## Destroyer551 (Dec 1, 2009)

How big did you say these were? I remember fishing at a local retention pond a few months ago that was loaded with daphina. They were around this big. -- or ---


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## mistergreen (Dec 9, 2006)

They're about 2/16 of an inch.


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## mistergreen (Dec 9, 2006)

Just wanted to add the adults are big enough for me to use a regular fishnet to scoop out the adults and leave the babies still in the tank.

I'm harvesting every week now and the population looks staple if not growing even more.


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## A Hill (Jul 25, 2005)

Nice that it all worked out well. Is it still going strong?

-Andrew


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## Burks (May 21, 2006)

A Hill said:


> Nice that it all worked out well. Is it still going strong?
> 
> -Andrew



Bump to that.


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## mistergreen (Dec 9, 2006)

oops, sorry, I wasn't updating this.

The population died off. I was using excel in my main tank to treat algae. That water wound up in the daphnia tank. I noticed a noticeable drop in the population. The basement temperature also dropped during the winter. It was in the 60s. That could also be a contributing factor.


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