I never had a problem with him. Since you said that your fish are messy eaters, leaving behind a mess, the ADF can find food. In case, you can always getting him some type of sinking foods - but I'm not sure what. I usually soaked a pellet or flake, and with a baster stuck it down, next to him and pushed the food to him and he'd eat it.
Breed for the breed, not for the money; the words any REAL breeder would understand.
You must know nothing in order to know all, for all is nothing and nothing is for all.