I have been using the Jungle medicated pellets for about a week now on a Green Terror that has the same issue. you feed the jungle for three days, then regular food for four days then back to the jungle for three days. I am starting to see some color in his poop already.
I am no fan of meds, but if it will save the fish's life I feel it is worth it. The GT wasn't eating at all, but did eat the jungle product. He went nuts this morning on some Omega One flakes, because it was day 4.
Good luck regardless of treatment method.