My Corey (~4 years old) is injured and it looks infected. I didn't notice this last night or this morning but the wound looks awful (see picture). I'm not sure if there was a fight but it lives in a 65 gallon heavily planted community tank with many 15 Enders, 23 Neons, 7 Kuhli loaches, 1 Hillstream butterfly loach, and 2 other Corey (1 albino and 2 of this type), and I also have 1 (very old) assassin snail.
I've separated him/her into a 10 gallon tank but I'm not sure what to treat with.
General cure? Melafix? Pimafix?
Also, do I need to treat others since it had this cotton/moss on its nose in the community tank?
Edit to add: 1) I just realized I didn't add water details. I will add tomorrow but all are "normal" for this tank. 2) I'm not sure if this is my male or female but when checking everyone else in the tank tonight, I realized my Corey laid eggs again after not doing so for about 6 months. All 3 of my Corey are over 4 years old.
