Few weeks ago, I had to cut off a tumour on my flowerhorn( which is growing back again). After that he stopped eating, and he got HITH. I can't get rid of his HITH problem. I used metro+ and took out the carbon, none of them worked. The flowerhorn use to eat cichlid excel, cichlid gold, cichlid bio gold abd cichlid staple. I change the water 2-3 times a week and I haven't seen any signs of improvement. What can I do to get rid of the HITH?