My one Cory has a light pink mark just below his fin, only on one side of his body. He is still active and swims to the top for air but he doesn't scavange like the other Corries. The other fish (3 Corries and 6 neon tetras) seem healthy.
I've had him/her for at least three months now and do about 25% water changes every week.
The only change is that recently we've been having power outages, about 2hours at a time, were the temperature drops with about 2°C but goes back to normal once the power comes back on.
I don't have an extra heater and filter to make a long term quarantine tank.
I've uploaded a photo of his/her pink mark
Last edited by Darkblade48; 09-09-2020 at 10:16 PM.
Reason: Please use the edit function for back to back posts to keep threads cleaner