I just found this thread since I was wondering if they are jumpers. I cover my tank but had a canister filter on for some detritus management (I rarely put it on the DT, maybe twice a year) and had the cover angled just enough to get the two tubes for the filter into the tank. About a 3/4" opening tapering to nothing over 5 or 6 inches. My flame hawk found that small opening and I found him dead on the floor the next morning. I'd never seen him jump before and I'd had him about 7 years. The most personality of any fish by far - he'd even swim into my cupped hand to perch, and as far as I could tell never bothered any shrimp (LA lists them as "reef safe with caution" for some reason).