gulper cats are mean with feeder fish, so are leaf fish (although boring). but a gulper cat if you can get it as they are voracius feeders capable of eating fish larger than themselves and rainbow snakeheads are not that aggressive i have kept one in a community tank, theyre pretty but thats bout it. brown snakeheads are good with feeders. what would be cool and different is a smiler, gray terrapin. could stay in a 30gal for a good period of time and destroy feeders, no teeth though.
... dumb fear of the unknown and how it runs our gov...