My Jaguars and my Jacks used to go nuts for live crickets 2x per week or so. Gutload them with pellets or if you are having trouble getting your fish to eat veggies, gutload them with veggies so they pass on the nutrients when they are in turn eaten by the fish. Local insects and earthworms are fine as well as long as they aren't taken from land that has been treated with pesticides, mine were particularly fond of Potato beetles, Japanese beetles and Junebugs, as well as house centipedes.
For fry an excellent protein-boost are leftover shrimp tails.....in other words, when we go out for seafood or make shrimp cocktail or other shrimp dishes, I always had everyone save a big pile of shrimp tails when they were done eating and I'd give them a quick rinse and drop them into the fry tank. The fry are so small they can get to the meat inside the small parts of the shell no human or adult fish would stand a chance of accessing, and it lasts for several days. The meaty remains in clam, mussel or oyster shells, (mainly the feet) are also a good choice.
