Panagrellus nepenthicola (Nemtode)
Banana worms are a close relative to the beer mat worm or microworm. They both eat yeast and can be cultured with a bit of yeast on some oatmeal.
Panagrellus redivivus (Nematode)
Perhaps one of the easiest and most foolproof foods to grow,
microworms are, as the name implies, very small, and are used for feeding fry.
Turbatrix aceti (Nematode)
They aren't eels, of course, but an aquatic version of microworms. Again - very simple to grow.
Panagrellus silusioides (Nematode)
Walter worms are almost exactly the same as microworms except they tend to remain active in the water column a little longer. Unless you're caring for bottom feeding fry they may be a better choice than microworms.