do you have any pets? Or worse.. one of these in the house??

http://images1.fanpop.com/images/qui...25_500_281.jpg

P.S. I am scared of the skull.

Do they come out to feed? With the lights on?

All of my fish hide when the lights are off I believe as a natural instinct to avoid predators (my theory lol.)

I have levels of "skitishness" among my fish with my fairy wrasse being on the high side. Whenever I come up to the tank he bolts. And my chromis also hides when I come up to the tank. Then it would be my tangs and last my clown who is the least afraid. But during feeding the only one who will hide is the wrasse.

Are you spending enough time around your tank ?
Maybe they need to see you more often to get used to you

+1, my fish are fine with me around but will hide when someone else comes over. I get right up to the tank, the fish will come check me out, I think they need time to get used to you and their environment.