She eats pretty much anything I put in there... earthworms, shrimp, pellets and I used to have 5 giant danios in the tank but she ate all but 1 that was spared and she leaves it alone now for whatever reason..
also she does get the gravel in her mouth when eating pellets because of the way she strikes at the pellets laying on the gravel... the lap spits the gravel out by shaking her head side to side and keeps the pellets in her mouth somehow... but I would assume that some of the gravel does get eaten but shes big enough and the gravel is small enough that it passes through.