Any omega-rich vitamin supplement could help. I use vita-chem, but selcon is excellent as well. Soak all of his foods, frozen, pellets, algae sheets... anything you can get him to eat. Different colors of algae too- green, red, purple, etc.
Also, do you use carbon in your tank regularly? Excessive carbon use is linked to HLLE as well...
Also, do you use carbon in your tank regularly? Excessive carbon use is linked to HLLE as well...