Daphnia Culture Instructions

[Crystal]

I have had a few requests for how I maintain my daphnia cultures, so I will post it for all to see. I apologize beforehand for it's length.

How set up and maintain a Daphnia cultures:

Tank: It is best to have a main "tank" and a backup - my backup is a 1g vase in the windowsill. I usually try to have 2-3 backups (anything under 5g doesn't need an airstone/filtration). Although I have had success with 5 one gallon vases on the windowsill for small applications.

Main Tank & Aeration: (glass tanks, or even clear plastic tupperware containers work)

I recommend a 5g or larger - thin layer of sand on bottom and gentle aeration (no tiny bubbles, as they will get stuck in the daphnia's shell and kill it - just leave the airstone off of the end of the tube). 1 bubble every 3-5 seconds is plenty, the daphnia live in still water. Snails and shrimp are welcome to eat any leftover food and produce inforsia for the daphnia.

I have found that aeration isn't really needed, simply using a turkey baster once a day to "bubble" the water for 10 seconds kept over 200 daphnia alive in a 1 gallon vase.

Backup tank: (try to only have 20-50 daphnia - or the culture can be overwhelmed and crash)

I recommend a 1g vase in the window sill, 1/4-1" of sand, a small plant or some moss, add some green water to kick things off, and 6-10 snails. The snails will produce inforsia for the daphnia, algae will also cloud the water. This vase should be self-sustaining for 2-3 months without a water change - just ensure to remove excess daphnia. Feed snails every week or so. No aeration or pump needed. Vase should always have at least a slight green tinge to the water, if you can't see an inch into the water due to suspended algae, even better.

Biggest problem with cultures:

The biggest danger is a another "bug" called cyclops, which present in most aquariums. They will decimate a culture in short order. So rule number 1 - never use tank water (or dip daphnia nets in other tanks). These bugs are smaller than the daphnia and cling to the walls, they are very quick to catch the slower daphnia and they reproduce even faster.

If you do get cyclops in your tank - know that it is only a matter of time before the culture crashes. Use daphnia from an uncontaminated backup culture to start another culture in another tank/container. Remember even 3 daphnia can fill a 5g in 5 weeks.

You will have to bleach the infected container for 3 hours, it is the only thing I have ever found that works - ensure you use a lot of water conditioner to de-bleach the residues. I have watched cyclops survive 3 days in water with chloramine.

Also treat any tap water going into the tank with prime or other condition that removes ammonia, chlorine, and heavy metals as daphnia are very sensitive to these things.

Food:

You can feed daphnia many things, algae being the best; but yeast, blended veggie juices, and other things work too.

Algae: easiest to grow on the window will - Use treated tap water, and add a few grains of miracle grow powder, stir well, and algae will grow swiftly. It is easiest to have 2-3 1G containers, empty one half ways and top up with new water and ferts. (I use a solar powered water pump to circulate the water and send my algae tanks into overdrive).

Yeast: the average baker's yeast works well. Use treated tap water and add the yeast (about 1 tsp per 500ml or equivilent). Do not overfeed yeast, as it consumes oxygen and can rapidly foul a tank. Water should be slightly cloudy and should clear up within 8 hours - if it is not clear then you are feeding too much, if it clears sooner, feeding too little. It is advised to feed green algae at the same time to help counter any water fouling.

Veggie juices: use a blender to blend carrots and peas (even frozen veggies work if you defrost them) into a fine slurry - use a nylon stocking to separate juices from pulp. You can freeze the juices in an ice cube tray, and use the pulp for snails, plecos, soups, or compost.

Finely ground dry food: you can finely grind foods (nls pellets, algae flake/wafers, fish food, etc) - it must be extremely finely ground - fine enough to remain suspended in the water column for 12-14hrs.

Mix in a small cup of water and add to the daphnia tank.

Water changes:

25% water changes every week or so are crucial (due to amount of food put in the tank and the fact that daphnia use a lot of calcium present in the water). Some people put a brine shrimp net at the end of a siphon so as not to waste daphnia. Refill using algae water, or water that has been treated for at least 3hrs. High phosphorus levels will slow daphnia reproduction, so if you daphnia culture isn't doing great, do a 50% water change and add green water.

Daphnia:

Daphnia females will clone themselves (most are female). They can start producing at 3 days of age, and live up to 28 days. A culture can triple in size every week.

Daphnia with white saddles are normal. Daphnia with black saddles means something is out of balance - the black saddles are eggs that will hatch only once they have dried out. Do a 50% water change and do a check for cyclops or other predators.

I sometimes force a small daphnia backup culture to crash just to collect the eggs - I then dry out the eggs and keep them as an extra backup in case all my cultures crash. The easiest way to cause a crash is to let them over-populate and then feed slightly less. Use an egg baster to collect the big females with black saddles and put them in a fine mesh net - they will drop the black eggs in 1-3 days. Note: snails love these eggs, so no snails in the net.

Or simply let the entire culture die in the vase and collect the 'dirt' (ensure no snail or shrimp are present).

Dry the eggs out and store them dry until needed (they are good for 3-5 years, but some may hatch even after 10 years).

Edited December 22, 2012 by Crystal

[425nm]

Awesome guide! Where would I be able to find a solar powered water pump?

[cainechow]

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