Algae Blenny food

[Bartman]

I got a small Algae Blenny for my Nano about 6 weeks ago and it has been doing an amazing job with hair algae in my tank. It is constantly active picking away at the glass and rocks. I would have expected it to be fat by now but it is not. In fact it appears to be slowly wasting away. Where my Clown and Royal Gramma always look fat in the stomach area the Blenny is now looking drawn and stringy. As I say, it always appears to be eating something but it does not go after flake or frozen food that the other 2 fish get and it doesn't seem interested in the few algae wafers I've tossed in. It is active and healthy looking otherwise. Any thoughts on what I should be trying to feed it?