There were some postings about this a while back when PetsMart was carrying them. From what I can tell, they are basically bottom feeders and prefer sand. Depending upon the species, they will grow to be 4-5" and I do believe they will eat small fish in your aquarium when they get older. Some say they are really a brackish fish but I don't know how true that is. Many seem to have trouble keeping them alive, and that may be the result of the lack of proper identification and info on care. The PetsMart where I saw them did not give a scientific name, which makes it very tricky. I think you can feed them just about anything that sinks, including frozen bloodworms and the like. Good luck, and I would love to see more pictures!