I bought a half moon betta at Petco on Tuesday and he has been housed in a 3 gallon tank from Walmart. That tank has a heater and filter and bubbling mechanism that keeps it nice and clean. Temp is at $75. I have given him pellets the first few days and now Im feeding him flakes and worm treats to try to get him to eat. He also swims kind of odd and it looks like a struggle. Petco has a 14 day policy on most pets, so if he came with a disease Id need to return him in a few days. I've jad a betta a few years ago and this never happened, and that one lived in a bowl!