well my rather small freshwater fish tank that has 1pleco , some platies and 3 other forget the name of them fish is filled with very small snails... i mean there everywhere (on glass , rocks , floors ) i have absolutely no clue where the hell they came from because i dint buy them and i just started to notice them lately. How do i get rid of them? is the only way pretty much take all the fish out and cleaning the tank completely?