Thanx everybody for the comments! To answer some of the questions the gulper is tryin to get at a lionhead goldfish in a floating breeder. I hand feed the gulpers and let them hunt on their own, so to prevent them from over-eating there's a breeder tank in my main tank where I keep extra feeders. As for what I feed the cats it's a mix of beefheart, sinkin pellets, live blackworms, bloodworms, earthworms, brineshrimp, market shrimp and fancy goldfish. Pet stores maintain fancies better than feeders so I'm less likely to get a disease. First the goldfish spend a couple of days in 10 gallon quarintine tank then they're released into the cats tank.