Could use a little help. Convict Cichlid turning black.

I have a 55 gal tank with 10 fish. 3 of those fish are convict cichlids. 2 of the cichlids are BEAUTIFUL. There coloring and fins are a sight to see. The other cichlid however has gradually darkened over the years to the point now that it's black. I can still make out the stripes and some shimmers of red and blue but for the most part she's black everywhere else. Ive noticed that the other 2 convicts have alsways stuck together and the other has always been the oddball out. Is there anything I can do to bring back it's coloring?

 

Do you have a pic? Turning black can be pretty natural for convicts, but a pic would be a better tell.

 

Pic

 

Not sure I can offer much help but the fish looks a little beaten up...

Welcome to fishlore

 

The Convict is subordinate & looks to be the lowest in the hierarchy. It's common for Cichlids to turn black when overly stressed or battered.

 

Going to move her to a tank by herself for a while. See if I can bring back those colors and heal some of the fins.