Blind Clarkii ?

I have a Clarkii which I bought around February. He's
roughly 2-2.5 inches long now. He looks as healthy as
ever but in the past several days he seems as though he's
in a stupor of some sort. Almost to the point of acting as
though he is blind.

All my water tests are right on. During feeding time while
the other fish (four other damsels) are swimming after the
food, it's just passing him by. Although it does appear as
though he's trying to find the food. But he's not bumping
into anything. Any clues. (75g FOWLR)