i have heard that clown loaches love to eat snails, but have heard that they can grow up to 10 inches r more. there are also some smaller varieties of loaches that will eat snails. You could manually remove them whenever u see them. You can also build a snail trap by putting some bottom feeder pellets or algae wafers into a clean plastic bottle. Weigh it down to the bottom of the tank and check back on it in a few hours. There should be snails in there. Just remove them and repeat the process.