Black spots on clowns. Any ideas why?

[PatientZero]

I got these clowns from Aquaman on the boards a year or so ago (maybe two now?) and he had them for a few years, so they are definitely adults. Lately I've been seeing black spots on the orange band of the male. I've had various clowns over the years and never seen this.

Any thoughts on what this is or why it's happening?

[ricenoodle]

rubbing up on frogspawn or other euphyllias usually do it. The fish is fine, just a skin response.