Cichlids that fight a lot have the ability to heal their skin damage far easier than more peaceful fish as long as your water is perfect. Crowded large predatory cichlid water is almost never perfect. Make the extra effort to see that it is or NO treatment will be effective.
When I used to breed Philippine Blue Angels, a very weak mutation, and they got a surface wound, I often had to use undiluted hydrogen peroxide on a cue-tip to sizzle off the white nasty infection down to the clean tissue, after that the wound would close and heal quickly on it's own. Your larger fish might require a cotton ball instead of a cue-tip though, just don't drip even a drop of the hydrogen peroxide into the gills. (that will seriously destroy the part of the gills it touches) If your water quality is good, which is difficult in a tank full of large preditors, it will heal up quickly after the HP treatment. Getting a few drops of the HP into the tank water will not damage the fish and will only turn into oxygen itself. Don't get more than a few drops total into the tank when you return the fish to the tank.