Moina experience

[JoshBA]

Quite a few months ago I discovered a small population of daphnia in my large paludarium, and from there size I determined they were daphnia moina. The tank is heavily planted, and plants were added from a few different sources, so there are many ways they could have ended up in there.

Anyway, I watched there numbers steadily rise, feeding off just the water suspended algae and bacteria available in the tank. Because of light, nutrient, and plant imbalance, hair algae gradually displaced the plants and engulfed the water area (largely due to me not really caring about it). I didn't really mind it doing so because it was providing excellent filtration to the system. So, just for the heck of it, and to give me a place to throw in excess algae and plants, I setup a 10 gallon window 'pond' tank.

Of course the daphnia ended up in that tank, so I decided to make good use of their apparent hardiness. So essentially all I did was drop an algae wafer in for the snails to eat, and as they consumed it, the daphnia gathered around filter feeding on the bacteria, and the daphnias' numbers increased. I've been doing this for about two months and its worked excellently. So, all in all, I've found this species of daphnia to be incredibly hardy and prolific , and would be ideal for newly hatched larvae, serving as an excellent alternative to using BBS.

 

[Bette]

That's really cool. Thank you for sharing the information!

 

[JoshBA]

I've also found that adding leaf litter significantly increases their numbers, perhaps even more then when using yeast. The leaves I've been using are dried live oak, which decompose pretty slowly under water.

The moina culture I've been maintaining has not once had a population crash, which seems to be an issue with most Daphnia species.

 

[sde]

Is it possible that the reason the leaves helped so much is because they are Oak leaves, and Oak leaves release tannins into the water? Tannins make the water more softer and more acidic according to one source. Could this be the reason? -Seth

 

[Bette]

Thank you again for sharing your experience with this! What do you do for maintenance on the window pond tank? Water changes, etc?

 

[kfamtvw7]

I've had Moina macrocopa in culture for about a year now and have experimented with different culture methods. There's a few of things I thought it would be worth adding here.

• Adding a little powdered eggshell to the culture does seem to improve production, I add around half a tablespoon to 5 litres of water.
• Culture vessel size is important - In larger containers if you do not have enough Moina initially their food will foul the water before they can consume it. For this reason it's important to start moina cultures in very small containers initially and incrementally increase the size as population increases. This is particularly relevant when feeding yeast or dried algae powder as opposed to live Chlorella vulgaris for example. I usually start cultures in a small jam jar and move up from there until they are in a 10L plastic storage tub. I also maintain a water barrel outside filled with moina, copepods and Chydora sphaericus.
• higher temperatures results in much faster reproduction, aim for around 25c.
• Contrary to what you will often read elsewhere I have found Moina less tolerant of dirty water than Daphnia. Production increased when I began performing weekly 100% water changes by filtering them through a very fine grade zooplankton mesh and discarding the old water.
• Adding snails to the culture does not seem to make any difference to production but can't hurt, the idea is that they will help clean up leftover food but also that certain snails possess a natural gut biome of infusoria that's passed out in their waste and that the moina will feed on this.
• I read that live plants in the culture vessel suppress production and was skeptical but my own experiments seem to confirm this. I don't know why this should be the case or whether this applies to all plants.
• Ephippia - Do not let your Moina form Ephippia. Moina generally by parthenogenesis but if conditions are less than ideal they will begin sexual reproduction. The females first produce male offspring which then fertilize the females who finally produce Ephippia or resting eggs. Having a dried stash of Ephippia can be useful if your culture crashes but it will take a long time for the culture to begin reproducing at the normal rate after a 'sexual reproduction incident'. Ephippia appear as black 'saddles' on mature females and will eventually be shed onto the floor of the culture vessel. If you want to produce ephippia deliberately then simply move your culture into the dark and underfeed, they will quickly begin sexual reproduction.
• freshish manure seems to be the best food for them, I don't know why but guess it may simply be due to the diversity of microorganisms they feed on from the manure as opposed to a monoculture of bakers yeast. I have used chicken and deer manure either added straight to the culture vessel or tied in cheesecloth and hung over the side but yeast or dried spirulina also work.
• Leaf litter leachate/ tannins - I have read a study where the 'leachate' from leaf litter was shown to extend the lifespan and brood size of Moina. In the study the leachate mostly came from pine needles whereas generally oak leaves are added to livefood cultures. Pine contains some chemicals that can be harmful to fish and amphibians so I would stick with oak. I don't add leaf litter to my indoor cultures but the outdoor water barrel naturally recieves a lot of leaf litter and it's thriving.
• I do not aerate any of my cultures in any way, this doesn't seem to effect production.
• freshly cut grass is also a viable food for them, it begins to break down very quickly and the moina feed on the resulting infusoria. Adding freshly cut grass to my outdoor barrel resulted in some noticable population explosions during the summer. Other than a few handfulls of grass added throughout the summer months and naturally blown leaf litter this outdoor culture was only ever initially fertilised with a layer of chicken and deer manure when it was started on 20.10.2016 and is still productive as of 02.11.2017 even though there has been frost. Obviously due to the lower temperatures and lack of daylight many females are now carrying ephippia.

I hope this might be useful to anyone thinking of culturing Moina. For larger fish and caudates Daphnia are just as easy to culture and ALOT easier to source but for anyone with larvae or fish fry Moina will prove to be an extremely valuable and nutritious tiny livefood. Their rapid reproduction at high temperatures means an outdoor stock culture can be maintained year round with minimal effort and that huge numbers of moina can be produced quickly as needed in a more controlled indoor culture.