Hydor has a mini heater. no regulation but it keeps pretty steady from what i've used on the betta and guppy bowls (1 gallon) it's flat even so you can place it under the gravel for a more even distribution. hope the little guy is doing ok, I had a problem with one of my Blue Gouramis getting picked on so i moved her to the 5 gallon guppy snail tank and do a 33/66% water change a few times a week for her. she's getting better BUT it's been a long time now. she reall did have a bad wound down to the meat.