I've had a couple over the years and they are hit and miss. They are on the aggressive side. The last one I bought was nice while small but then turned into a terror. It eat the dorsal fins off my Blue Line flasher and chased my other fairy wrasses. If your setting up a fish only you would be ok. I'll never take the chance again! Major pain to remove from reef tank:mad: JME
Mine is pretty territorial. Doesn't actually attack his tankmates but always puffing up and trying to warn them to move. Mine has created a little cave in the sand where he sleeps