Orange Shoulder Tang

[Azzkr]

I have a adult orange shoulder tang that's about 9 inches long since I switched my lights to LED he is turning yellow now back to juvi colours. He is still eating lots and its not the water quality. I haven't added any new fish into the tank either other than a juvi queen angel that is a inch and a half. I know when they are changing to adult colours they will change back to juvi sometimes. Has anyone else change back to yellow when they are full adult colours