Ok so ive got a 20g community tank thats not suppost to have snails, must hae come in with some shrimp or a peice of driftwood, i dunno. but I counted at least two dozen about 2mm across. Im told assassin snails will take them out my question is how many should i get, Im assuming theres more snails then I can see but at this point there so small that they can hide in the gravel. Any advice? What are the odd that my pictus cats will eat some snails? Help