Diamond goby and firefish

[Jakester79]

I have had my diamond for a few weeks and he only stays in one small area of my 75 gal. He comes out sometimes but besides sifting through the live sand I don't know what he eats. I just figured he would move around the tank more. My fowler has been running for 2 months.
Also I just got a firefish the other day and he has disappeared. I know they can jump out but my tank is covered. He was out and doing fine but haven't seen him in awhile. I have a clown, hippo tang, the goby, domino and yellowtail damsel(that doesn't bother anyone) and a bicolor pseudochromis. Any thought?

 

[obscurereef]

Firefish can hide for a week before becoming adjusted to the aquarium. If the damsel isn't a bully, I'm sure the bicolor dottyback will be. My firefish darts into his burrow only when my cleaner wrasse comes near. They are just really docile fish so I wouldn't worry about it too much.