Hi, I'm wondering if anyone has any advice on heating small tanks. I work at a pet store, so I'm quite knowledgable when it comes to aquatics, but we don't sell heaters small enough for my 2 gallon (currently has 1 balloon-bellied molly and an otocinclus) and my 1 gallon (with a betta) and I'm not too thrilled about the idea of spending another $15-20 on a heater for each tank. I have a space heater in my room, which keeps the room around 65 degrees when I'm not in there, and about 75 degrees when I am (don't want to burn the house down you know). But I can't help but think my fishies aren't warm enough. I leave the light on the 2 gallon on all day (hence why I have the otocinclus to help with algae) but the 1 gallon doesn't have a light. Any suggestions on how the keep the water warmer other than those expensive heaters?