I happened to notice a round brown spot on my glass today, and took a closer look. It's a SNAIL! Now where do they come from? It appears to be eating the algae on the glass....which thrills me since both my otos died. But how did I get it? And what does it need to live? Do I want it to stay? It's about 3/4" in diameter I'd say, and brownish in color. I don't have any live plants in my tank right now, but I did at one time before I started treating for ick. Is that where it came in? Do fish carry them in?