Please do not treat it. It reflects the biodiversity of the water body of your farmed water lilies, it shows that the water quality you use is better and not too polluted, it will also purify your water body and water lily leaves, because its food is decaying aquatic plants. It also adds a bit of color to your farmed landscape. Don't you think it would be more beautiful with water, flowers, fish and insects? As for the snails being poisonous the claim is for consumption. Most snails carry parasites and should be eaten with caution! The snail in your picture is a type of mud snail, which is often eaten around Shaoxing. Just do it cooked and kill the pathogenic microorganisms thoroughly before consumption!