Large gash on my watchman goby

[Logzor]

I just noticed a large gash on my watchman goby. This fish is at least 6 years old and has been healthy and is around 5 inches long.

He is moving around just fine doing his nightly activities but he has a spot on him with exposed flesh (1 cm?) and it is bulging somewhat. In the tank are chormis, clowns, and a tomini tang. No crab or other large creatures...

What could have caused this and will he heal up ok?

 

[Mikeeee]

Thats weird. I have a purple fire fish and i just noticed the same thing.. not sure what did it yet.. all other fish are fine.