growth on lawnmower

[tubbanorman]

I bought a Lawnmower Blennie about two months ago. resently There is a growth on it's side. It looks like a white bubble on it skin. I have never seen anything like it on a fish before. The "blister" about 1/8" round. Any ideas about what it could be?
The lawnmower is still as active as ever and is always munching on the rocks, glass and caulerpa. I don't see him scratching it on the rock either.

[OrionGirl]

Could it have gotten stung by something? I've seen a similar mark on a fish that I know was tagged by a coral stinger. It went away within a few days.

[tubbanorman]

It's possible. I have some yellow polyps which could have done it?
The only other corals in the tank are mushrooms, kenya tree and toadstools. It has been on him for about two weeks.
Come to think of it, it might have showed up right after I added the yellow polyps. None of the other fish show any signs of anything.
I have one other polyp that I can't identify that came in on the live rocks. It was only about 1/2 in diameter but now it has doubled in size. It is pinkish/peach with a hint of green on the inside. I saw it in a picture from the doctor foster and smith catalog, page 103 but it doesn't say what it is.

[tubbanorman]

The growth is getting bigger on my lawnmower. It is still active and eating. I wish I had a digital camera. It seems to be coming through the skin and bubble like. Anyone haveany ideas?