So using Melafix helped it clear up? Usually the suggestion is to make sure and use the medication for longer than you think is necessary. If Melafix helped then I'd probably use Melafix again.
Also, I'd toss the carbon that you used to take the medication out. If any nasty bacteria were also absorbed then you dont want to release that back into the tank. Also think about anything that you put into the tank while the fish was affected, nets, test tubes, siphons etc and make sure to sterilize those because you might just re-infect the tank if you use them again after its cleared up.
I hear about people sometimes using Pimafix and Melafix with each other...you might try that? But if it worked before, I wouldn't hesitate to use the Melafix again.