How to know when a fish is too big for its tank?

[anthonygf]

I would get a small captive bred yellow tang and keep it until it becomes a problem. When it does donate it to your local fish store.

That is what I was prepared to do with my yellow 3 years ago. Still have him. When I saw him at the local Petco he was very skinny, fins shredded. I talked to the manager to complain about his poor condition and they let me have him for $20 or so. He is fat and happy now.