this might be a stupid question, so i apologize ahead of time
i have a 5 gallon tank for my betta and there is a heater in it. i think i have the heater that is made for 2-5 gallons. i don't have a thermometer on the tank (i am getting one tomorrow). my betta, rooster, swims around and he's pretty healthy i think, but he spends a lot of time huddled up under the heater (especially since it's been colder the last few weeks). should i get a different heater? is the rest of the water too cold maybe? maybe i should get a heater for the 5-10 gallon size? thanks in advance for your help!