When i started my first and only tank i bought 4 bunches of plants to put in my 10 gallon. I saw a few teeny tiny little snails crawling around but didnt think any thing of it. a month later there were a bagillion snails in my tank. its been about 5 months now and i put in about 15 ghost shrimp. a week after adding the ghost shrimp the snails have practically disapeared. I'm not sure what has happened. Any thoughts?