I was cycling a tank for about 3 weeks and then added one betta fish to it 7 days ago. For the three weeks that I had the tank running without a fish in it I saw nothing in it at all. This is a 5.5 gallon tank with live plants. I am a beginner and had no idea that live plants might have snails in them. Now I know that live plants can have snails but I am puzzled because for 3 weeks there were no snails at all in the tank. About 4 days after I put the betta fish into the tank I started to see little tiny things crawling up the side of the tank. They are brown in color and there are also some bigger black snails crawling around on the bottom of the tank. My question, where did the snails come from if they weren't there before I put the fish into the tank and then they just appeared 4 days later after I put the fish into the tank. Where did they come from and now do I get rid of them? I did manage to catch some using some lettuce in an open turkey baster. They crawled into it but I did not get all of them and each day I have to manually remove them. They literally make my skin crawl and I really want to get rid of them.