Is it possible for my percs to turn all black

I'm certainly not an expert on the subject, but I though this usually this dosn't happen from hosting in a nem? Of course, an LTA isn't a natural host for them, so, maybe they are not adapted to handle the particular nemocytes. If it is though, it isn't supposed to be an issue other than looks. BTW, I have noticed this in my ocs hosting in a frogspawn, but not to the degree they seem to be turning black. Maybe a combination of things happening. They can continue to turn darker for several months.

 

yeah idk either, they are def turning black, they started out with just a few spots and then more and more each day..

see how this fin is starting to turn black in this pic..its now a majority of it black, the black edges are getting wider and thicker black..

this pic is about a month old..you can see a couple spots, now there are a bunch