Silver dollar teeth

[Eggheadfish]

Hi all,
I have two red hook luna silver dollars and the male, Benedict, seems to be having trouble eating lately. He is not gorging on algae wafers like usual. I got him to eat a clump of tubifex worms but it's hard since they are skittish. Has anyone experienced teeth problems with silver dollars before? They look brown

 

[Eggheadfish]

Anyone? I'm still having trouble getting him to eat. He will every one out of four days or so which is uncharacteristic. Any help is appreciated.