White spot on Splendid Dottyback

[BlueReefer73]

A few days ago we noticed a saddle shaped white spot on our Splendid Dottyback. A month agonour two spot tang had something similar. It went away after a water change. This time it happened after a water change. Equal on both sides just before the dorsal fin. He is behaving normally, but the Coral Beauty has been chasing him and nipping more than usual. Could this just be stress?

 

[vetteguy53081]

These pics are extremely dark blue and all that can be seen is a fuzzy outline of fish.
Please retake under white lighting.

 

[Idoc]

It could possibly just be damage from the other fish bullying him. As long as the fish is eating normally, breathing regularly, and generally acting normal, I would just watch the spot for changes in size, shape, and coloration.

Even if it's not a disease and just an injury, it could become infected. Just have a hospital tank and meds ready in case you need them rapidly.