Today I noticed a white film/blotch on my blenny's mouth. He was opening his mouth quite a bit and it seemed like there was a thin translucent white film attached to his upper and lower jaw. I don't really know how else to explain it. I got a picture of him with his mouth closed and it looks like there's a white blotch on his lip. Has anyone seen this before? He's been in my tank 4 days and I didn't notice this white thing on his mouth until today.