Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Most fish will eat all sorts of insects and many other things. Some bugs are clearly marked (like wasps) with bright colors and fish generally leave these alone. Some bugs are not so marked, but are not good for the fish. The fish seem to need to learn to avoid these bugs.
I think ant larvae are safe, but I would not risk adult ants.
I have fed:
Aphids (put the aphid covered leaf in the water so the aphids are under water, not on top.
Worms- both earth worms and the larger night crawlers. Size according to the fish (smaller worms for mid-sized fish, medium sized worms for my largest fish. Leave the largest worms to reproduce in the garden)
Snails. These are the snails originally imported for escargots, then they escaped. Also called garden snails. I feed these to my largest Clown Loaches.
Mosquito larvae: All my tanks get some when I can find them, but I generally do not keep standing water around.