I had a cory develop that on an injury to one fin. I caught him and dabbed a little hydrogen peroxide on it with a q tip. No more fungus.
I'm sure you know to check your parameters and do water changes.
I'm not sure if you can see the discoloration on this pleco but I can see it on my phone.
Yes they are
Dang. Should I bring one back to the pet store? I didn't know that they were aggressive to each other. Would a male and female be aggressive?
The only home is back at the store.
Would it be wise to replace him with a different pleco species or should leave the one with free roam?
I did notice that the pleco that has the stress related discoloration has more white fuzzy stuff so maybe they did get into a fight. I saw them this morning like violently flapping and waving their fins.