help, my blue damsel is black

when i turned on the light in my tank this morning i noticed one of my blue damsels came straight out of the rock work and was a purplish black color, is this anything to worry about...the only time i ever saw this was during the transport of the fish from the lfs to my house

....on a side note my tank is not on any timer so i turn it on by hand and i turned it on a little earlier today since i had somewhere to go

 

update: i just checked back on the tank and he seems to be his normal blue and is back inside the rock work, should i be worried

 

Don't be worried about it. My blue damsels did the same thing before I got timers . As you said earlier you turned on the lights earlier than usual. This may have caused some stress to the fish making it alter its color due to the light being turned on at a different time than they are used to.
Also at night some fish change color. A few months ago I was looking for "pods" at night with a flashlight in the dark and my damsels were a slate color and the other day I was looking for "pods" and my Coral Beauty Angel was grey.
As long as it goes back to its natural bright blue color, I wouldn't worry but, I would consider getting timers so your lights go on the same time everyday to limit the amount of stress due to fluctuating light changes.
If I may ask, What size tank is your damsel in and what type of lighting are you using?

 

the damsel passed and it was in a 20 hex with the normal stock hood lighting

 

Sorry for the loss.

While difference in coloration can indicate a health issue it's normal for damsels and other fish like yellow tangs to show a noticeable change in coloration after the lights have been off or in response to stress like bullying.

Was this a new fish and what other fish are in the tank?

 

hes been in and doing well for atleast 4 months and the only thing else in there is a diamond goby, cleaner shrimp, and a condy....i also have an emerald crab and a hermit crab but nothing seemed to clash in the tank...it was a shock when i found him like this this morning

 

My diamond goby was dead this morning too now, however my inverts seem to be fine....i had class this morning so I didn't get the chance to test the tank yet, there does not seem to be any signs of parasites.....what could be the cause of this?

 

test your water, when were your last tests/WC? what filtering system do you have (skimmer, LR, sump, etc.)

sorry for your loss never cool when an animal dies, lost a yellow tale damsel myself (only loss thus far thank God....and knock on wood) trusted the shop keeper that said 3 could easily get along in 47 g, the other two killed the smaller one over night and just before the death like corailine rightfully pointed it out it was almost black in color from the stress.

this said when my two YTBD go to sleep (one in each end of the tank) they also go a little darker in color.

 

Sorry for the loss. That's not good to hear that both fish went.

 

Are these fish dying at night?