Tangs are also territorial. They are like some people who really need their own space and prefer to be around a limited number of people at any one time. They are very, beautiful and interesting fish, but they come with characteristics that prohibit them from fully thriving in small areas. They grow extremely fast and also must have a certain space amount to actually spread their fins and get their swimming excercise. Think of them as some dog breeds. Every seen a greyhound or a boxer locked up in the homeowner's home for a while? It can be done, much like having a tang in a small area--however it's not favorable. These dog breeds go crazy over time b/c they were bred to run and get a certain amount of excercise. When they don't get it, that energy is exerted to something else...such as becoming aggressive or completely opposite...depressed. However, a nice little Shih Tzu will be thrilled to be in an apartment. It's excercise needs are not that extensive and the apartment to dog size ratio is much smaller. It's also like having five year olds inside, without recess for a week! They really go crazy. LOL. I hope this helps you and gives you a much better understanding of Tangs' needs.