Both of my boys live in a 5 gallon fish tank (separated of course...). They were living in a 2.5 gallon though, I switched them to a larger one just because of my preferences. My oldest is over 2 and my youngest is about 1 year or so. When I clean them I put something called Betta Conditioner in, I'm not sure if its required or not though. I've never heard of any sort of tablets. My Bettas eat betta pellets and blood worms, I can't think of the pellets brand name at the moment though. I hope that helped some, there are many more people here who have a lot more experience with bettas than I do so hopefully they'll reply...