Well, that is good then. Just now I lured all three of them near the surface with tropical fish flakes. Tommorow I'll need to get snails to clean that up.
You shouldn't have much of a mess if the fish are eating all the food. Just make sure you only feed them as much as they can eat in a few months. Something to try might be pellets; I feed my pond goldfish pellets. They float on the surface and don't sink the way flakes do. The pellets come in small and larger sizes, depending on the size of your fish.