Mealworms (Tenebrio beetle larvae).

Mealworms are actually the larvae of beetles, as you know. They are usually available at your LFS. Of the two common species of Tenebrio, the yellow mealworm, T. molitor, is more often seen than the dark mealworm, T. obscurus. Either is reared on dry wheat bran or oatmeal or cornmeal. A little dry skim milk powder boosts the reproduction rate. A piece of filter paper that's been lightly sprayed with water provides the minimal amount of moisture these beetles require.

Mealworm larvae contain 48% crude protein and 40% crude fat. Too rich for a constant diet, these pale grubs are relished by those larger fish that can handle them. And if you're willing to slice them in cross-sections with a razor blade--— the mark of true devotion--— your smaller loaches will slurp them up like cannolli!