here is the mesh like stuff i've been talking about. you can buy it at walmart, lowes, and home depot. although i think the kind you can get at lowes and home depot is a little bit larger and wider roles, as well as a little bit thicker and more durable.
basically, its this spongy type stuff you use to put on the shelves in your kitchen, and to line the cabnets and drawers in your kitchen to keep plates and other things from getting slammed down on hard surfaces.
its perfect for lining the side of the canopy b/c air can still get through it, so the canopy gets the benefits of being an open top with air exchange, but will keep the jumping fish from ending up as crunchy carpet treats. i also like it b/c since the tank will be in a living area, i dont want the glare of a metal halide bulb in my peripheral vision or a glare in the TV while i'm trying to watch it. other benefits are that its light weight, easily removable. and you can even aim a regular room fan at the canopy and pretty much all the air will still get through the mesh.
to reduce glare, you may need to do up to 2 sheets. its just something you'll have to play with.
here is one sheet, as you can see most light passes through, and it only reduces a little bit of glare. but its still completely permeable to a good breeze coming through the room. and any fish that tries to jump will hit it and land back in the tank. i havent had a single jumping casualty from any of my tanks since i've started using this stuff 2 years ago.
and this is what 2 sheets basically looks like