Considering how expensive those fish are, I would assume that anyone buying this fish also has a very large tank and doesn't need to think about if said tank is big enough. I don't mean that in a negative way to the OP or anybody else... it just seems to be true. I'd go with a minimum of 120 gallons for just about any tang as they are such active swimmers. Sure, they CAN go into smaller tanks. The fish simply won't be as active/healthy. Super cool fish regardless!