My only update for the day. He isn't any worse, far as I can tell. His eye is nearly better, you'd only notice a slight bit of cloudiness if you scrutinized him and caught him in the right light.
He has lost a touch bit of his dorsal fin but only the little nub that was already hanging in the previous picture.
I've opted to dab the edge of his dorsal fin and the black edge on his bottom fin with echinacea tincture as I find it for myself personally to be amazing at clearing an infection and I have found that it is used in some products for aquarium fish in the USA which are added to tanks. So, I decided that means it is safe enough to apply topically. I was careful to only swab it on the edges of the fins which are worst affected.
I am reading that Metronidazole is not generally the best antibiotic for fin rot, but I haven't read anything that says it would have any negative effects. Sounds like it will either help or have no effect at all. I am debating how long to use it. I am going with the article that says to dose 100mg/40 liters every 2 days with a 25% water change before each dose. I have found other articles saying to dose 250mg but I'd rather go easier and stick with the lower dosage. I will be picking that up shortly.