Iāve had my fish tank since August and Iāve been able to avoid getting a heater since I live in Florida. Now itās going to start getting in the 50s and I really donāt want my water to get cold. I have a 5.5 gallon tank for my betta fish. What heater should I buy? Iām scared because a lot of reviews Iāve read for different ones says that they overheated and killed their fish. Let me know. Thanks.