I just give them fish every couple weeks or so, but they love it. It is not their staple diet; mostly I feed them mice, chicks and quail. But they love whiting, tilapia, haddock. Really any fish. Fresh may be best, but I just thaw out a few strips of whatever is in the freezer. It is just a minor part of their diet and I doubt if fish filets would be nutrionally adequate as a major diet component without the skeleton and internal organs. They have also eaten cornsnakes, kingsnakes, toads, chunks of road-killed rabbit. Any vertebrate I get my hands on is fair game. It is fun to experiment and they seem to thrive on a varied diet.