I bought one of Marineland's visi therm delux heaters 25 watts for my betta's 3 gallon tank, took it home, set it up in Edward's tank and plugged it into the wall. The red light went on but it didn't heat up so I took it back to the store and exchanged it for the Marineland plastic shatter proof...
Ok, thanks so much! One more thing, I don't want to start another thread so I was wondering if I also need a filter to circulate the heat. I already have 1, but even when it's on the lowest setting, poor Edward can barely swim against the current.