Okay before I begin, I would just like to let you all know that I have a blue Betta Fish named Merlin. He lives in a one gallon bowl with only pebbles. I know that the one gallon bowl is not good for him and he could be much happier in a bigger bowl, but that is not an option at the moment. I do a 30-50 percent water change every other day with dechlorinator. I mantain his tank the best I can (if there's anything else let me know!!!). So I will move him into a 5 gallon tank as soon as I can, so please don't hate on me for his bowl!!! I know he can be happier. So, he is really happy and swims around and flares at pencils. However, he does not have a heater. Our house is usually about 76-80 degrees so it has not been much of a problem. However, I know how much these guys like warm water and I would like to get him a heater in case the house temp drops and so that he will be happier. However, I know this can be quite a challenge for small tanks!!! So do you guys have any suggestions or advice as to which heater will be the best for my little guy? Thank you for reading through this long post and thank you in advance for your help.