dont stress too much bro, im sure its just a stage he's going thru and hes prolly eating a lil bit when your not looking. whats your temp at? try bumping it to 83 and add a lil salt. the temp should increase his metabolism and the salt will work as a mild laxitive to see if he can clean out a lil. if he still doesnt eat you might have to mix up your own lil dose of food and use a straw and feed him like that just to get food in his belly, but ive never had to do that so... If worse comes to worse i just sent ira a bunch of fry or you can grab a couple lil guys off me. did you check your water perameters too? this just sounds too wierd to me but good luck bro