IMHO snails are the pits.
I have a tank setup at a freinds place - due to my lack of space - and that has tiny snails in it (I could care less what species they are). They seem to breed like mad then run out of food and die and pollute the water. Not all of them seem to die as the tank eventually gets a water change and the process starts over. It is a pain in da ...
I had a goldfish left over from my coldwater days that I put in my tropical tank and he was a great snail destroyer. He cleaned up the snail problem without charge. When summer came I put him in my parents pond as he was getting big and I felt sorry for him having to be at 28 odd degrees. Still no snails in the tank he was in.