Yellow clown goby, reef safe?

[Pennywise the Clown]

The yellow clown goby has always been a fish that I wanted in my display. They always seem to have lots of character.
I asked my LFS to get me one and they text me today that they have several in stock. I went along and they had 5 fish, all a nice size and looking healthy. 3 were in a holding tank and 2 were put in amongst corals, mainly LPS and zoas. It was one of the fish with the corals that looked the healthiest so I was just about to ask the owner to net it for me when the little bugger went up to a duncan frag and preceeded to rip tentacles off!!!
I suddenly had this nightmarish vision of my prize duncan getting shreaded and I left the shop fishless.
I was always under the opinion that yellow gobbies were reef safe but this one obviously wasn't. Is this a one off or are they not as reef safe as I believed?

 

[James M]

Some are reef safe and some aren’t. Like angel fish

 

[Bob Loblaw]

Everyone Clown Goby I've kept has nipped SPS but ignored everything else.

 

[James M]

Nipping at sps is normal

 

[mort]

They strip sps tissue to lay their eggs in the wild, plus they also live in sps heads naturally. It's less common to see them going for lps but not unheard of.
It's actually been proven that in the wild they keep corals healthier.