The most popular and desirable of live foods for aquarium
fishes is Daphnia. this generic name includes several species,
the most common of which are D.pulex, D. longispina, and D.
magna. this listing is according to their size, an important
factor when baby fishes must be fed. All species breed in the
same manner and require the same general care.
Raising Daphnia is a simple matter if their life cycle and
requirements are completely understood. Sex in the Daphnia is
rather easily ascertained as the female carries eggs in a brood
sac. These eggs appear as tiny dark spots when the animal is
held in a small glass container and light is allowed to pass
through it. Initial cultures should have a dozen pairs as a
starter, at least. Experience has shown that a culture will
reach its peak of productivity about 3 weeks after the culture
has been initiated.
Outside cultivation of Daphnia is much easier. Pools should
be fertilized with sheep, cow, or horse manure. A week or so
later some Daphnia should be introduced. If the pool does not
freeze, the culture should be available all year round.
Frequent addition of lettuce leaves is helpful. Earth-bottom
pools or all-concrete pools are used to equal advantage. the
parasite problem is manifest in the outdoor situation.