I have one at home in my 340 gallon. He's about 3 inches long. Absolutely gorgeous and always out. I just happened to stumble into him at my LFS a couple months ago. He's very territorial, and occasionally chases the coral beauty pair, as well as dive-bombing the chromis shoal about 4 times a day or so. I wouldn't put one in with fish that can't handle some aggression in a tank under 6 feet long with lots of holes to escape into.