Welllll.... Lol! I have 5 bettas in my washroom, one in a 5 gallon, one in a 2.5 gallon, two in a 4 gallon split, and one in a 1 gallon or 1.5 gallon. Three others are just in 1 gallon containers because thy are sick. In my room I have the rest, two 5 gallons, one 2 gallon, one 2.5 gallon, two 10 gallons, two 1.5 gallon, one 4 gallon, and two 1.6 gallons. The rest are in 1 gallon beanie baby cases that get 100% water changes every 3 days. LOL!