I've been doing some reading and I just wanted to know what you guys thought about keeping tanks without heaters. I know a few people do, but what about the rest of you. Would you go without a heater? Some people say "Yes, fish NEED a temp of, say, 76F" and other say "no, the science of blah blah blah allows the fish to live in cooler than 74F water because of how they live in the wild blah blah blah" The reason I ask is because I have several tanks laying around with filters and everything, but no heater! I want to set them up, but temps in my house can drop pretty low (68 is normal for upstairs and 60-65 for downstairs in the fishroom). I'm not saying I will be setting them up. I like to have a heater just to be on the safe side. So what are your thoughts?