Moina are small freshwater crustaceans also known as “water fleas” because of their hopping like motion. The main difference between Daphnia and Moina is their size, Moina are smaller with young about the same size as newly hatched brine shrimp while Daphnia can grow up to 5 mm. Moina also are tolerant of a wider range of temperatures and water quality and cultures are 3 to 4 times more productive than Daphnia cultures making them better suited for hobby cultivation.
I will focus on Moina Culture for the rest of this article however; Daphnia can also be cultured using the same techniques. Moina is one of the most nutritious live foods available for fry and since they live in fresh water you don’t have to worry about uneaten ones fouling your water. They require a bit more space to culture than many other live foods but are relatively easy to culture moina.
Items Needed For Moina Culture:
1) Moina starter culture – available online.
2) A spare 10 gallon tank with a light and air.
3) Some water from an existing tank.
4) Food for you moina culture – Baker’s yeast or spiralina powder.
First fill your 10 gallon tank with some water from an existing tank. You can mix it with dechlorinated tap water if needed to fill the tank. Add an air stone to the tank to provide some light circulation. You don’t want the water to be turbulent; you just want a little circulation to keep food suspended. Adding a small mesh bag of crushed coral will help provide calcium and buffer the PH.
For optimal production, Moina require a PH of 6.5 or higher, a temperature between 75F and 80F, and 12 to 24 hours of light per day. Once your tank is set up you can acclimatize and add you starter culture. To feed your culture, dissolve 1 teaspoon of yeast in a pint of warm water (optionally you can mix in a little powered spirulina too). Once cooled, strain about an ounce though a brine shrimp net to filter out any clumps and add to the tank. The amount fed is dependent on the amount of Moina and the clarity of the water. This is the hardest part about growing Moina as you must learn to adjust this as needed.
Feeding should be done on a regular basis at about the same time each day. If you happen to be raising snails or just have a lot of extra ones, you can add some snails to the tank and just feed the snails instead of feeding the Moina. The snail droppings contain lots of bacteria and encourage the growth of infusoria for the Moina to feed on. You can also seed a lightly aerated quart or gallon jar with Moina and snails so you have a backup starter culture. To harvest your Moina you can simply use a brine shrimp net to scoop them out. Once a week scrub any algae from the glass and turn off the air to let the tank settle. Then siphon off any debris from the bottom of the tank and replace the water removed with dechlorinated water or water from another tank.
Moina are perfect for your small fish like guppies, neon, betta, baby Axolotl, etc. Moina are also perfect for baby fish or fry since their size is really small. They are also perfect to condition your Guppy fish for breeding purposes.