Blue cheek goby missing tail

[Flo5777]

Had this blue cheek goby about a year, nothing new in the tank. Except it appears something has eaten its tail, unless it's disease & I haven't noticed.
Any ideas/advice? Thanks!

 

[KrisReef]

The second picture shows two things Could be connected, the gobies caudal degradations appear to be cleanly shaped and match reasonably well with the mouth shape of the Clownfish in the background who is swimming perpendicular to the injured fish as if contemplating another bite.

 

[Flo5777]

I think you could be right, the clown fish bite me if I dare to put my hand into the tank. I did wonder if it could be the emerald crab, but don't think the tail would be so rounded, it surely would be more torn?

 

[Mr. Mojo Rising]

crabs can't catch a health fish.... and the goby staying up near the top like that near the glass is a stressed defensive position. You should separate the tank or remove one of the fish. How big is the tank?

 

[Flo5777]

It’s a Red Sea reefer 170 he’s often at the top & exceptionally greedy. He’s got massive since I’ve had him.
He’s gone to his sandy under rock hiding spot since this picture at breakfast, which again he ate an awful lot of.