Daphnia is not that exotic a food

As the Forum eccentric, I raise Daphnia all summer. I have fed my fish this high quality live food almost every day since April. From April to Hallowe'en, I have had a replenishing food source for 3 years now. If you have a backyard, here is a possibility...

I use 20 gallon plastic tubs. I caught Daphnia locally a few years ago, and divided them up over three containers. They sit in the shade, and the two main ones are covered in a screen, to keep out breeding mosquitoes. It works. The bottom of the tubs are covered in decaying leaves, from last Autumn. Every October, I put the tubs on the ground and drain them to about 8 inches. the Daphnia eggs overwinter in the leaves I add in, and the cycle starts again in Spring. I fail miserably at growing them indoors in winter, so it is a seasonal food source.

I feed dried yeast and the occasional mouldy fruit. I had some peaches go bad recently, and threw both of them into tubs. The Daphnia went insane, and I removed enormous numbers to condition my fish. It's what most of them eat in nature, although the Canadian species is different.

It takes very little space, a tub, a screen and some dead leaves and yeast. And of course, a starter culture. A 24 inch by 24 inch spaces in shade will do it. I sweep a net through daily, empty it into a jar and use a turkey baster to feed anywhere from one to twenty tanks, depending on how I do feeding them. That's my Achilles heel - I still haven't found the perfect, consistent easy food source for these prolific crustaceans. If I had that sorted out, I could probably overwinter some indoors.


That's a day's net sweep from a couple of weeks ago. Free food!

Hi Gary. I was thinking of trying this this summer and was wondering at what temp does the colony stop breeding at?

As long as they were in shade, my outdoor colonies went all summer long. I expect them to return within a few days now, and I'll be harvesting until october.

Thanks Gary

I keep a small colony going indoors all year round. It is used more as a seed colony rather than for feeding since it is in a 5 gallon tank.. They do fine on green water and yeast suspension.. The real trick when feeding yeast to them is to go very light on it. If you have green water for them , you can't give them too much. Occasionally I get a heavy bloom of the daphnia, and if I don't scoop a bunch out and feed to the fish, they will have a huge die off because they will exhaust the O2 in their water. My colonies outdoors are in a plastic garbage can and in a kiddies splash pool .. They get enough natural feed from leaves fallen into the containers. I get a flush of them in spring when the water first warms up and can harvest heavily , in summer the water warms too much and I have a big die off, and then another flush of them in Fall when the water cools again.. The Fall daphnia crop continues until the water freezes for winter.

Set a pool or large container out where it will naturally go green, or seed it with green water to jump start it ..When it is thoroughly green , dump in a starter of daphnia. You won't see much but green water for a couple of weeks or more and then almost overnight the water will clear and be absolutely crowded with daphnia. Harvest them or they will multiply and die off from crowding and subsequent O2 starvation .. If you have large harvests of them you can freeze daphnia in ice cube trays to use for feeding to condition or treat your fish when live production is low.

Would some aeration help in the summer heat or is it purely just too warm?

I can't keep them indoors. I've tried. I've used Daphnia pulex, my local wilds, and am told if I can get Daphnia magna, I would do better.
But there is no summer die off outside.
This year, I am ready. I have a corner of the yard that is a dead end, and isn't very useful. I got some close to new tanks recently, to replace some very ancient ones. Rather than throw them out in Spring, I decided to use the old tanks for the summer, for Daphnia, in my hidden corner area.
Last year, I could feed 20 tank 3-4 times a week - this summer, luck willing, I'll be able to do a lot more.
I am feeding a mix of brewer's yeast and soy flour, in very careful amounts. There is natural leaf litter, but the dried yeast really raises the numbers, and is dirt cheap at the Bulk places.

Gary, what do you do about rainwater? Does it mess up the tanks?

Nah, I let it rain. That's how I water change.

GaryE wrote:
This year, I am ready. I have a corner of the yard that is a dead end, and isn't very useful. I got some close to new tanks recently, to replace some very ancient ones. Rather than throw them out in Spring, I decided to use the old tanks for the summer, for Daphnia, in my hidden corner area.

Or is the corner hidden to avoid any problems with the rest of the family?!

How do you seed the tanks in spring time?

Biulu wrote:

GaryE wrote:
This year, I am ready. I have a corner of the yard that is a dead end, and isn't very useful. I got some close to new tanks recently, to replace some very ancient ones. Rather than throw them out in Spring, I decided to use the old tanks for the summer, for Daphnia, in my hidden corner area.

Or is the corner hidden to avoid any problems with the rest of the family?!

My vote is you are spot on, Biulu!!!

How are the daphnia growing these days ?

Any luck ? I am interested in your progress. I have seen GaryE with lots of success, any one else brewing these guys ? (I say brew because you use yeast...)

May have to try this and see if I can find some around here to breed.

I've ordered some "eggs" but they;)  have not arrived yet.  Soon hopefully though.

Repteel wrote: I've ordered some "eggs" but they;)  have not arrived yet.  Soon hopefully though.  

Interesting! Where did you find these?

Trying ebay first but it's a bit over do.  My backup plan is these guys, http://ww  w.merlan.ca/productdetail.aspx?id=12978.  They are teaching supple co, but you need to order over $50.

I ordered daphnia eggs through canadian aquatics when I was in CAC. (If you google canadian aquatics charles lam you will get the site). He sells daphnia, food and eggs from the West Coast.

alexmtl wrote:I ordered daphnia eggs through canadian aquatics when I was in CAC. (If you google canadian aquatics charles lam you will get the site). He sells daphnia, food and eggs from the West Coast.

Didn't know about him. He's my new backup then.

So I also have tried this. I had a ten gal at work, and brought it home mostly as it was one of those critter topped ones. the wire top for mice or hampsters. It took a while to get going, but I now have some daphnia. but not many. I actually have a good number of mosquitoes.
Fish seem to love them.
I think I need more leaves and more yeast.