Right now I have an overstocked 5.5 that does fine because of the lots and lots of plants I have. Even though I have a really good thing going, I want a mystery snail. Knowing full well I am at the brink of working well and everyone going belly up, I need to know just how much of an impact a snail is. It is equivalent to another betta? Gosh forbid, a goldfish?!? Maybe closer to a shrimp or two? Also consider that it is possibly a temporary situation for the snail as I will be setting up a 10 or 20 gallon in the next 6 months.