Thanks Richard,
My tank is 20g and all parameters are normal. The algae is not the
blue-green slimy bacteria stuff but an almost powdery green furry
(short) stuff. I had some of it on a piece of live rock but my turbo
snail ate it. I guess he didn't get it all tho.

I guess a better question would have been "What fish can I buy that
would eat it as a supplement to its diet?" If this were a fresh water
tank I would not have a problem picking a fish, but I just don't know
enough about salt water varieties yet.

Vicki