Any freshwater fish. I'm not familiar with Tuffs though. Are they like Rosy Red Minnows? If so, then yes they have as much as a goldfish. If you are bound and determined to feed your predator a "feeder fish" feed it any type of Damsel. Know why they are so fricken fast and a pia to catch? They have to have speed in order to get away from the predators. Damsels, Gobies, Anthias, etc are feeders for lg marine predators. Kreblak- what kind of fish are you going to put in your reef? As long as you don't put any Puffers, Triggers, Lg Eels, Groupers, etc you should be okay to keep smaller fish.