Coral eating Blenny. Is this normal?

Hey guys....need some advice. I am kinda new to the saltwater set up. Been doing fairly well I think. I got a beautiful nano tank set up thats primarily a coral set up. Only fish are a bi color blenny and a very small red scooter blenny. This tank is about a year and 4 months old and well established. The blenny has recently begun to pick off parts of some of the corals and shrooms. He hasnt hit any rics, zoos or rhodactus but is constantly pecking parts from the flower pot coral ends and now picking at the fringes of some of the mushrooms and polyps. Is this normal....I thought they were reef safe....algae eaters mostly.....Should I take this guy out? :-/

 

I take it this is the bi-color?
Bi-color's are known to sometimes be nippers.
Also keep in mind there is NO 100% guarantee with ANY fish. I have a hippo that loves to nip at kenya, and only kenya for some reason.

 

yeah...sorry...to clarify...its the bi color blenny. I got a kenya but it doesnt seem to harm this one. Is been nipping more and more frequently it seems. I keep him in there cause he keeps the live rock cleaned up! Now I dont know....