Chromis Behaviour problem

[silentcivilian]

Ok, so all 3 of my chromis are acting very very very out of character.. and Im wondering if I should be worried. They hide.. all the time unless food is in the water.. even then, sometimes dont come out.. they appear fine in color and still seem to be of a good size.. but to make things clear.
Smallest: Hides behind the heater at the back of the tank on the left side or inder the left side aquaclear.
Middle sized: Hides at the front right portion of my tank at the top of the glass with his mouth almost out of the water
Biggest (about the size of a big clown): Hides in the rock work in the middle of the tank..

Chromis to my understanding are grouping open water fish.. and until a month ago did such as a group of 3 for almost 2 years.. now see above to see the huge change..

Why would they change this much.

New corals to system - several leathers
New fish to system - 1 red scooter blenny, 1 red mandrin, 1 yellow clown goby