Need Cromis advice, should I be worried?

Hey guys,
So I've got my 10 gallon SW tank running. Been about 1.5 weeks and I've added two Cromis to start slowly. A nice, cheap and cool looking buy so I was happy about them. They looked great all day and when I turned the LED (fluval eco bright- 200 lumens?) light I have to "sunset" (a deep blue/purple) before bed, they still looked ok but after about two hours I came back down to shut the light off and all of a sudden they looked so sickly. They're eyes looked black, they looked like Forrest green and were very lethargic. I sat there and watched and thy went to the bottom as if they were going to sleep and then when I woke up, they were perfectly fine. All color was restored. They were active and such. But tonight the same thing happened...any idea???

Thanks,
Frank

 

Parameter swings maybe?
Temp?
Salinity?

 

Temp is 78 degrees
Salinity is a little under 1.024

 

They are going to sleep.

 

My damsel always gets pale at lights out.

 

+1 with Vinny, I used to have a tropical fish tank, my mollies and other brightly coloured fish used to lose their colour every night as the went to sleep and get it back again in the morning, as if by magic.

My money is, they are going to sleep.

 

Yup, their color lightens up as a form of camouflage. I wouldn't be worried.

 

Totally normal. Some are much more extreme than others. My rabbit fish changes color so much,nit looks like a totally different fish. Night time reef survival. This is one of the amazingly cool things about our hobby - observing nature up close.

 

Phew, thanks guys!

 

ps, like mentioned, they are perfectly ok this morning! running around and bulldozing one an other for a pellet of food