i just did a water change, he is by himself in a half filled tank (i did this because less water= less meds used , and hopefully will be more effective).
also, i couldnt bear to see him covered in fungus so i netted him, and scrapped him with a soft, wet sponge. only then i realised, how bad his injury is. he lost maybe almost half of his scales and skin, his blue fins, and 2/3 of his tail are all gone except for his pectorals, will they grow back?
one improvement is that he gained back his previous strength, he was barely able to move 2 days ago