my new chromis keeps hoping into the overflow box. its annoying as hell to get him out of there and hes already done it about 4 times in the last 5 days
Yes something is harassing it. Keep in mind that they are a schooling fish and dont do well without that school. The minimum I would go with would be 6 and preferably more. A single fish is just going to be continually stressed.
its not being harrased. I have it in a school of 3 damsels. They are the only fish in the tank, besides a pair of black and white percs. Its not being harased, its probably just curious and swims around the overflow and then gets sucked in. I wanted to put some kind of screen there, but is stainless steel safe?
If there's no way the fish could fit through, then yeah, eggcrate would work.
Ya know, come to think of it, there's a pretty neat baffle/screen setup they use for the pelagic jellies. Basically, there's a low-flow overflow on one or both ends of the tank (they try to keep currents rather "circular" for the jellies), and set and glued (at an angle) to the base of the overflow is a screen, basically on a frame. There's no way any animal can be sucked into this thing because the flow is so diffuse in the mid-reaches of the water column.