Hi so I have a new Betta fish who seems happy, I read that the temp should be between 25.5 and 26.5 degrees, however the seller advised a broad range of 24 -30 degrees, my tank has been around the 26.6 mark, the little guy is swimming all over the tank but just seems to really like it by the heater, is he just happy there or is he looking for warmer water?