Yep, I have a yellow tang on a 20 gallon tank, I'm nuts, I didn't want to but I was having problems with some algae that nobody else is eating, so I did lots of investigation before buying it, I was not going to buy one of those for my tank because that's not the recommended tank for them but I had no choice, that's why I got the smallest one I could get so one day either I get a bigger tank or I change him for a smaller one in the future.