[Delphinus]

Eggcrate man. All fish have the capacity to jump. Any burst of speed in the ocean takes you to .. another spot in the ocean. That same burst of speed in a tank takes you.. out of the tank. At least if there's a lid there's nowhere for them to go but back in.

Yes, it's ugly, but .... if you have that black tracking stuff (forget the name) then it can sit inside of that and look OK. If you have bare glass then the eggcrate needs to be cut a little larger so it sits on the edges. In that case, it looks like crap, but what can you do. I have this situation myself. I don't like the look of it but to me there's no question -- no canopy == lid or no fish.

Sorry to hear of your loss. I know your pain, last year I lost my pair of fairy wrasses to jumping because the canopy was mistakingly left open overnight (I was on vacation at the time). Tanksitter came by and found the two dried fish on the floor. Some fish are more prone to jumping than others (fairy wrasses are pretty bad as it turns out), but *any* fish can jump, so definitely put a lid on that tank.