# Culturing Daphnia: personal experiences and resources



## AndyT. (Jun 28, 2006)

I was asked in another thread to detail how I did successfully cultured daphnia for a number of years &#8230; so here it is, everything I remember about culturing daphnia.

I want to address why culturing daphnia would be a desirable thing. My experience was that when I was feeding my fish live foods (daphnia, blackworms) I had fish that were vibrantly colored all the time and the fish started spawning without my doing anything at all to encourage the spawning. My angelfish spawned so regularly that I remember actually looking in the show tank one night and thinking, _Dang, those stupid things have done it again!_ I had run out of tank space for the fry and was developing a deep, personal hatred of brine shrimp cultures (daphnia are too big for new fry).I wish I had owned a digital camera when I was culturing daphnia. The coloration of the fish was shockingly vivid. One time I traded in six rosey barbs to an LFS and they were so brightly colored, a customer in the store purchased them before I even left the building.

There are different species of daphnia that hobbyists can culture. These different species have very different needs. For example, the _Daphnia magna_ I had the most success with preferred pretty vigorous aeration, whereas the _Daphnia pulex_ would die off under those same conditions.

I got my daphnia cultures from LFS Cultures. This was back in 1993, I have ordered from them several times since then, most recently around 2000 and I have always been very pleased with them. When I have time to culture again, I plan to order from them.

*Equipment for culturing Daphnia*

Some kind of container that will hold water. It does not have to be an aquarium, I have used buckets and big Rubbermaid bins. Aquariums are fine too. Minimum size is five gallons. This is for the Daphnia culture.
Another similar container that will hold water. This is for a daphnia culture as well. You weren't planning on being silly and relying on just one culture, were you?
A couple of handfuls of crushed coral, oyster shell&#8230; anything that will mineralize the water and make it alkaline.
Two or three air pumps and some airstones. I am a fan of the Coralife Luft Pumps - they have a true rheostat that adjusts the flow of air without creating backpressure on the diaphragm. I also like the big oversize airstones because they stay sunk. Small airstones float.
A fine net, brine shrimp nets are good for this. Make sure it is of reasonable dimensions, 4" minimum. Trying to harvest daphnia with a little 1" brine shrimp net is a waste of time.
Purified water for the cultures. Daphnia are sensitive to heavy metals and dechlorinated tap water is a good way to kill them. I simply ran my water through a carbon filter when I cultured them and that seemed to do it. Today I would use RO water.
Food source for Daphnia. That is discussed below.

*Setup*
I always used aged aquarium water in my daphnia tanks. LFS Cultures recommends that you use water inoculated with "sheep, horse or cow manure." Since my cultures were indoors during most of this time, that wasn't gonna happen. Fill your culture tanks with water and get those airpumps circulating water. Throw in a tiny handful of crushed coral, oyster shell or whatever. That will keep the water alkaline and provide tiny amounts of calcium and magnesium for the daphnia to make their shells. Ideally, let the culture tanks sit for a few days. Then you can add your culture of daphnia.

*Food for Daphnia*
There are a lot of different ways to feed daphnia. But the bottom line is this: *daphnia cultures rapidly die in contaminated water*. That fact impacts the success of various feeding methods dramatically.

_Yeast_
My experience with feeding yeast was that the cultures always crashed shortly thereafter. I don't recommend this method of feeding.

_Manure_
My one, brief, outdoor experiment seemed to be going well until my wife threatened me with physical harm; she did not like our patio to reek of manure for some reason. Neither did the neighbors in the townhouse.

_Pre-made Daphnia food from a supplier_
I'm 99% sure this is just manure. It smelled just like it. See above.

_Strained peas, sweet potatoes_
While the cultures did okay, this was a labor-intensive pain in the keister. Once a week grinding veggies in the blender into a liquid. Straining the liquid through a coffee filter to insure particle size was small enough. Storing it in the refrigerator. Trying to gauge when you have fed enough, trying not to overfeed&#8230; it got old.

_Green water: the best way_
Back then, I usually had three ten gallon aquariums full of green water to supply two ten gallon aquariums of daphnia with food. You never want to have less than three green water cultures going. And keep in mind, when those cultures crash, they crash quickly. But the flip side is, all you need is aquarium water, light and water circulation. They will go for months.

Also consider this: back then I knew nothing about plants and fertilization. Can you imagine if you applied a variant of the EI fertilization scheme to a well-lit aquarium with aged water in it? You would have *GREEN WATER FROM HELL*. I bet that my biggest mistake leading to culture crashes was not understanding what the single celled algae's needed in the way of food. I was giving them most of what they needed, but not enough of the correct fertilization. No wonder they kept dying every few months&#8230;

_Possible considerations today_
Today you can buy many different concentrated algal cultures, solutions and frozen pastes. Almost all of them are for saltwater, but I am thinking that if you fed them in small amounts to the daphnia, they would not care. You'd have to add a large quantity to raise the salinity to harmful levels, and that would constantly be diluted by the maintenance routine. Also, it appears that many species of daphnia are tolerant of brackish water!

*Maintenance and Harvesting*
I had a sweet system down. First, drain the daphnia culture tanks completely, straining the water through a fine net. All the daphnia are collected in the net, all the nasty water gets tossed. Often I would have a 4" brine shrimp net literally full to the brim with daphnia - I guess it would weigh between an eight and a quarter pound. Then, add water from the green water tanks into the daphnia culture tanks. While this is going on, feed the majority of the daphnia to my other aquariums. That would keep them fed for several days as the fish hunted down the hundreds of daphnia. When the daphnia culture tanks were full of green water again, return the remainder of the daphnia to those culture tanks.

The next step was to do a water change in the big 150g South American Cichlid tank - the tank that was filthy no matter how much I cleaned it. That water was used to refill the green water cultures.

Usually in three days the greenwater cultures were back to a solid green so thick a ruler held inside the aquarium became invisible an inch from the glass. By about that time, the daphnia would have cleared out the water in the culture tanks and be ready for more green water and the cycle would start again. I had it down so that I could do all of that in about forty-five minutes! Depending on the density of the cultures I harvested daphnia twor or three times a week.

*Closing Thoughts*
Was it worth all the work? 90% of the time - yes. I was rewarded with stunning fish. It was interesting to learn about the biology of the daphnia and study them. They are kind of cool all on their own. The 10% when I was dealing with culture crashes and trying to save them&#8230; that was awful. I have a small problem with perfectionism and I could not let go and just start over. That made the whole thing very stressful. I mention this because I find a lot of my fellow aquarists share this personality trait.

*Resources:*
General
General information about daphnia, not specific to aquariums 
Wikipedia on daphnia

Culturing
Good overview of culturing daphnia
Thread from the Krib about culturing daphnia
The scientific approach, from Cornell University
Live Foods Mailing List Archive. Man, it is a shame this died. It was an excellent resource.
Aquamaniacs Live Food Forum; this one is new to me.

Purchasing
LFS Cultures
LarvaTech
There are other sources for daphnia, you just have to look!

I will be checking this thread for questions, but life is being very busy so it may take a day or two for me to get back here.


----------



## epicfish (Sep 11, 2006)

Thanks for the great thread. I just wish I had somewhere I could keep aquariums to maintain a green water culture! =)


----------

