im not saying it cant be done, heck you can throw him in a 40 breeder, but it is best to have larger tanks for fish that are constantly swimming like tangs to keep them not only healthy, but happy. just because it can be done does not mean it should be. ill admit, ive dont it, but i did it with a 90 gallon tank sitting in my garage waiting to be transferred over. if you really want a yellow tang, again, fiind a small one, but make sure you are dedicated to getting a larger tank. tangs get big, and they need the space to thrive.