The fish I'm going to keep that eats the feeders in Belonesox Belizanus (pike topminnow). Belonesox pretty much only eat fish. However, they aren't as aggressive at going after those fish as say an oscar or many cichlids.
I've thought about Syndontis catfish, but they typically prefer more subdued lighting. I have two 55w PC
's and a 40w flour. over a 75 gal
tank. Though this lighting is not extreme, it might be a little bright for the Syndontis. I've also thought about loaches, but not sure they would do well in the brackish water (though the water isn't that brackish, about 1/2 tsp salt per gal
of water). I really don't want anything that gets too big. I'm not really interested in going to a bigger tank. I could always keep a couple of channel catfish and release in my backyard (I live on a 17 acre lake). However, that really isn't my first choice. I could also keep a couple of crawdads, though would really rather keep fish.