Some help please - pic added

[Noj]

Anyone who can help or give suggestions I'd appreciate it.

My two clowns have formed some sort of dark coloured spots on them. The spots dont seem to be in any order or specific size or shape. It resembles ink dots. To my knowledge, the fish are rubbing themselves on the bottom/corner of the tank once an hour or so. Scratching whatever is on them. I assumed it was ich, but all my research says ich is small white spots. These spots are dark in colour and bigger then a grain of sand.

All my levels are correct. I've had the fish for 1 year now. They are the only two fish in the tank. I have recently (10days-4 weeks ago) added some frags and live rock from OA in Vancouver. I add a calcium additive now as well.

I am trying to get a picture of it, but its proving to be fairly difficult to get a picture that shows.

Someone? Anyone?

Thanks alot,

-Cam