What is this spot on my Mandarin Goby?

Hello All,

Just noticed this spot on our Mandarin Goby last evening. He is acting normally, eating and swimming as usual.

Sorry for the blurry photo - will try for a better one but hoped maybe someone was familiar enough with the options to have suggestions.



He just recently started eating frozen brine and mysis shrimp. Don't know if that is relevant.

Hoping this isn't a big deal but worried.

Thanks for any ideas or advice.

 

Mandarins sometimes collect detritus secondary to the presence of their mucous coating. That could also be a mechanical injury from rock work or aggression from other fish. Personally I would get some pods and add them to the tank, soak all food in selcon, do a little research on melafix. Hopefully it is one of the benign things I mentioned and not the beginnings of a bacterial infection.

 

Thank you for the reply. We've put some pods in the tank and soak foods in Selcon. Will research melafix.
We do have a Combtooth blenny that occasionally swipes at him, so maybe it is simple.
Thank you again!