I noticed this spot on my cardinal fish today. He's eating normally, but this sore looks terrible and I think it's gotten a little worse since this picture was taken.
I'm trying to catch him to put him in the sick tank, but I'm not sure I'm going to be able to. I may have to treat the whole tank, but I'm not even sure that's feasible. Any advice would be appreciated.
The tank is a 125G tank, and I have three clown fish, a pajama cardinal, a talbots damselfish, a lawnmower blenny, anchor corals, colt coral, a long tentacled anemone and a bunch of polyps and mushrooms. I need to know if treating the tank would hurt any of these. I know I can't use copper, but I'm hoping someone can tell me what this sore looks like and what to treat with.
EDIT: Forgot to mention that all water perameters are normal, except the nitrates are a little high, but they're always the same, have been for years. Also, I read the Maracyn-Two info an apparantly it is not toxic to inverts????? So if I can't catch him, I could treat the whole tank? (I would need 12 tablets the first day and 6 tablets for days 2-5. I can't imagine having to treat the whole tank!) I have Melafix as well, and it states it's safe for the bio-filter in the sand bed and for inverts. Melafix Marine is supposed to be safe for corals. I can get that one today if ya'll think it's safe.