Help !! Dommino not doing well

[Captainhemo]

Ok, I've had the lights back on for a bit now and the fish definately looks much better than last night although there is a still a bit of " paleness " to her. She is much more herself so far though .
I have given them a bit more mysis and it was eaten quickly as usual. She has also seemed to have eased in her aggression twards the smaller fish.

I dont understand this, what would cause such an abrupt loss of colr (black) and then a return to normal or bery close to normal ?
She did not look well at all last night when I wrote my intial post, almost all her " black colro " had disapperared and like I had maintioned last night, she seemed very aggitated