I'm trying to change the food of my fishes from flake to pellets. I try to feed them with the new food, but they won't eat it. They just suck on it for awhile and spit it out. Should I starve them for a few days and try to feed them the new food again? The previous food I had was Tetra-min Pro and the new food is New Life Spectrium. My tank is a community tank with livebearers, rainbows, gouramis, hatchets, angle fish, cory cats, and clown loaches.