Hello, I'm a newbie to the saltwater tank world. Previously I had a freshwater for about 9 years that was successful. In our fish buy, we got a sail fin tang without the knowledge that my 90 gallon tank will too be to small for him. What do I do in this scenario? I've never sold fish nor do I know how too. Do local saltwater fish stores buy fish sometimes? Or even take donated fish? I'm sure the sail fin wasn't cheap but I more-so don't want him messing up the tank in the coming months if he grows to large. Thanks for any thoughts!