Darks marks on fish

[wilmerdj21]

Hi I need some help I have a 4 clownfish 2 percula and 2 ocellaris on the same tank in the last 2 months the bigger one is a ocellaris and is chasing the bigger Percula all over the tank. In the last month I noticed that the percula is getting black marks. Is this a disease or something else. Maybe is because is getting bullied all day. I will post a photo any help is appreciated.

 

[Lasse]

In the case of mechanical injuries such as a bite from another fish, black or dark areas can sometimes form around the healed injury. The black or dark color is melanin that forms around the injury to act as an antioxidant against the peroxide that the fish's defense mechanisms produce to kill bacteria in the open wound.

Don't know if this is the case for you in this case but black or darker areas after a mechanical injury is not uncommon among fish and it is normal - no need to panic.

Sincerely Lasse

 

[BryanM]

#fishmedics will want 15-30 seconds of video under bright whites, posted to youtube and linked here, to try and help ID what's happening.

 

[Largeangels]

Hard to tell but it looks more like this percula has some Onyx lineage so the orange areas are just filling in with black as it is growing. I don't see any damage to the fins which is usually where the damage first occurs if its from the other clown.

You may need to seperate the percs out of the tank if this gets more aggressive.

 

[Sharkbait19]

I agree it just looks more like normal patterning for the breed.
That said, sometimes fish will change patterning/colors depending on stress or aggression. Keeping 4 clowns together is eventually a recipe for disaster. They really are best in pairs, solo, or large harems (the latter of which can be hard to successfully build).