i have in a small heated container (about gallon i know it small but its the best i could could do) the man at my local fish store gave me some flakes soaked in garlic (is that alright?) i tryed feeding him them but he would not eat them.
First I would move him into a smaller tank- 2 gallons. (small tanks are easier to clean.) Once you have him in a smaller tank do 100% water changed every day, with a tsp of aquarium salt per gallon for ten days. Moosh up garlic and soak his pellets in the juice and feed those three times a day, roughly. Or two, whichever is better for your schedule. Keep at it until his parasites go away.
In a ten gal, maybe... 100% water changes every other day or 50% water changes every other day.