Mine didn't accept pellets until he was 7.5 inches, but that might have been because I have the medium sized pellets, lol. Well actually I cut them in half before and he still didn't take them. My silver was on flakes until then and I would ocassionally throw in a pellet to see what he'd do. He'd suck it in his mouth try to chew for a bit then would eventually spit it back out. Then at 7.5 in I decided to starve him out. He only went 1 day without food before caving in, lol.