Whenever I saw red on fish I treat with something that both deals with bacterial infections and soothes / slime coat. In other words, I would have done essentially what you already have done. But sometimes one bacterial med may work where another doesn't. So I would suggest maybe something that ends with -aracyn or -cillin.

Thanks for your thoughts. Update: late at night I looked at him with a flashlight. For some reason they panic less - like a deer in headlights? At any rate, could see fully formed gills ie layers so on, but NO gill covering. (he would occasionally turn so I could compare sides and try to measure gill so on - I could clearly see well defined layers of 'gill' sorry forget scientific name, but just was missing that top outer cover with scales and coloring. Like if our skin were torn off, pink. No oozing, no mucus,nothing else. He as I mentioned has been like this when I saw him first at store - many weeks now. So seems he survived with this damage. Swelling has gone down as well.

I found some info late last night that mentioned a particular bacteria and or parasite (forget now) that erodes the gill covering when not treated early enough (dang those stores, I kept telling them to treat that tank) and this is what seems to have occurred.

I have treated for both gram neg/positive and external parasites. I have put all but three red eyed columbian tetras into the main tank. (20 gallon long, planted with annubias, rocks and two outside filters) 9 Red eyed columbian tetras and three mystery snails. He is in with remaining two with mouth 'fungus' ie probably flexibar bacteria. Just now using more natural methods and off meds, I find spot treating, salt, and pimefix sometimes works better for patches of this hard to treat bacteria- I think he will be fine just don't expect gill to regrow? He is really fiesty, and I guess will do fine and I will need to keep a watch on him. Thanks Sherry

Glad to gear that he is recovering. My old supervisor always suggested trying different bacterial meds, if one doesn't seem to work. He may not have been up on the gram negative / positive terminology, but I think he recognized the concept. Another thing he taught is to leave the meds in the tank without doing a water change for at least a day, so as to give the meds full opportunity to affect the disease.

Lol, I am not so 'up' on it either, though I have lots of science behind me. I just have one question for you. Assuming the whatever caused the damage is now gone, can he (and so far he has) survive without the gill plate or cover. Just looks a little vunerable, but as I said, he is pretty strong and so far sans the missing gill plate doing fine.

I have a terror in the main tank now. The one red eyed that terrorized the diamond tetras, was put in 20 long prior to others who were being treated, being added. They are now hanging (that float in 'space' look) on the left side of the tank and he is terrorizing anyone that dares to move into his space; over 2/3 rds the rest of the tank. I added more floating long rooted anubias and then fake silk (used cork to float them) and still they do not come out. I don't blame them, he moves in fast to make sure they stay in the corner. If I move him into a smaller tank for a bit, as I have heard this done, what do you think of him rethinking his bully tendancies. The school is about 10 strong, and I am really suprised that the school didn't temper his temper!

Thanks also for the med info.. I wondered, but don't like the uneaten food at bottom (middle feeders in smaller hospital tank seem to miss the food) so guess I could use turkey baster to clean up bottom.
Thanks again... Sherry