I would suggest going back the the LFS u got the fish. and ask the owner what they feed the fish...
Thats what i did.. my arowana ate some feeders, then mellows.. after awhile it just stop.. I was curious and i went back the the fish store.. found out the owner feed it dried shrimp.. so i bought a can of the same stuff and now its eating it like crazy..
Course i will start changing up its diet again.. But thats always the key.. start by feeding it what its used to getting, and start little by little with diff food.. If its 10" i think in time it will eat.. make sure they "float" tho.. arow thens to be apathic towards food that do not float or sink...
Good luck!