could be just coloring up. to be honest ive not seen any illness that would discolor fins so evenly, especially in a pattern like that that is easily recognized as butterfly pattern. for that i wouldnt worry too much. Depending on age when you got him can just now be noticable. also his body could be a little faded from either illness or the meds making it more noticable (or different tank with different lights etc.)
cheers
I totally agree. Fin Rot does not necessarily come with coloring. The signs are more like uneven tail edges, spilting tails, and holes in the fins. Look at his fins real close with a magnifying glass and if his edges are smooth and evenly distriuted around the fin shape then he probably does not have fin rot.
And be careful with the meds. Too much will do harm. Also be careful with large waterchanges. The larger the water change, the harder it is to match temperature and pH. Just do freaquent (daily) 25% changes. Water changes are stressful to the fish even though it helps them. They hate the invasion of their territory caused by many water changes.
