[Peter Finke]

Andy, we must speak more exact and speak about species. It is not sufficient to speak about the genus Moina.
You have Moina salina in mind, I spoke of Moina macrocopa. The first is a saltwater form and I have no experience with it. The latter is a freshwater form and it is that Moina which is talked about when we have Parosphromenus in mind. I learn that some Killifish friends use M. salina, but all is much easier mth M. macrocopa.
You are right with your remarks on Ephippia. I cannot say anything about M.salina, but there are Ephippia with M. macrocopa. However, to my knowledge they cannot be stored and canned like the cysts of Artemia. I only once encountered them indirectly in my M. macrocopa vessels: The adult animals had died for some reason and I did not clean up the vessel (because of laziness). Nothing was swimming around any more for days, even weeks. But about a fortnight or three weeks later there were Moina again. I never have encountered this a second time, but in principle it proves the existence of Ephippia. Unfortunately I was not able to repeat that by experiment. Unfortunately they obviously cannot be stored in a dried form as we woud like they could (as e.g. Daphnia). Maybe this is different with M. salina; I don’t know.
Your remark on the reason why you don’t use saltwater organisms for freshwater fish (to prevent the extremely pure water to be enriched with minerals) does not fit to your speaking of M. salina. Maybe, M. salina is comparable to Artemia salina: There is no reason to be afraid of destroying the labile blackwater milieu if you wash that food in soft freshwater before feeding by using a sieve suited to the tiny organisms. I never had such problems. They still live for some hours even in softest freshwater, but you should feed only tiny quantities that are eaten within minutes. The huge advantage of M. macrocopa is the fact that they need no saltwater, could be fed nearly directly and could live for days in your tank. Even the adults are rather small, and then there are smaller forms of all ages. The youngest of them are as tiny as the freshly hatched Artemia naupliae. And contrary to Daphnia they are soft, without hard shells, the fish eat them eagerly and could become fertile by them. This latter is the same with Artemia.
However, mostly M. are not easy to get hold of; in Germany we normally get our starting populations from other breeders. They could easily be fed by baker’s yeast, and algae and some special solutions are possible too. There is one great difference to breeding Daphnia pulex: The m. macrocopa live in a high density of food particles; if they are not fed every day anew the animals can be lost within days. But if the proliferation once has started, a tiny vessel could produce so much most excellent food for quite an assembly of pairs and their young.
So, I would conclude that M. macrocopa (sometimes they are called M. macrocarpa; I don’t know which is right, the former it seems to me) is the right Moina for Parosphromenus.
At the first international meeting next September in Hamburg we will sell starting populations.