I had one for a while. My issue with them is their size. Unlike so many of the Chaetodon species, H. diphreutes gets really big, really fast. And being so tall, they just end up looking ginormous in a tank. Also, unless you have a BIG tank with lots of open swimming space (ie the fish can swim in a straight line without having to turn around), their dorsal fin tends to get smaller as they grow. I saw a magnificent school of them in a shark display at a public aquarium. Their dorsal fins where incredibly long!