Help with spot on Clownfish pectoral fin

[MagnumMoose]

I noticed this spot on the right pectoral fin on the top where the fin runs into the body. The fish will on occasion scratch on a rock, but it doesn't seem to bothered by it. It eats well and seems to be growing fin. It is the solo inhabitant of the tank besides a few hermits and snails.

 

[snorvich]

A single persistent "what spot" is likely lymphocystis. If it goes away in 4 days or so, that would be a different issue. Photo is not sufficient for diagnosis.

 

[ThRoewer]

A single persistent "what spot" is likely lymphocystis. If it goes away in 4 days or so, that would be a different issue. Photo is not sufficient for diagnosis.

It doesn't look like ich. I also don't think it's brook (though with clownfish I would always keep it in mind).
To me it looks more like something bacterial.
I would keep an eye on it to see if it gets larger/more or shrinks/less.
Just in case I would get formalin and a broadband antibiotic to be prepared.