He may not need any more meds. Fin and tail rot is easy to clear up usually. Their fins, however, will take weeks, even months, to grow back, and may never do so. Or may only grow partly back. If the fins look ragged, but the edges are the same color as the rest of the fins, the disease is gone, and he needs time to grow fins. If the edges are thick and whiter than the rest of the fins, he still needs medication.
Yes, after doing the water change, run the carbon for 24 hours, then you can remove it and re-treat, if necessary.
In regards to the nose, he is probably showing he is stressed, and the color has just faded. Once he is healthy again, it should come back.
answered 1 month ago
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