When I had fish I went from 1 gallon to 5 gallons to 20 gallons to 50 gallons. And if the tortoise bug haven't bitten me who knows where it would've stopped The tank had to go to make room for the tortoise but it was a lot of fun to have, and amazing what little maintenance it takes once you do get it set up right. People kept telling me that the bigger the tank the less work it was which doesn't make sense until you actually do it.