I had a fire eel I kept until it got to be about 34 inches or so. It only ate tubifex worms until I tried nightcrawlers from a fishing bait store. It loved those! After that I fed both daily but that was costly as the nightcrawlers came in tubs of about 12 and it would eagerly eat 2 daily and most likely more if offered. I tried other fishing worms (such as red worms) with no success. I did not however try unearthing my own. I agree to make sure they aren't full of pesticides tho.