Was told that clowns were not jumpers so I ran topless until I lost two in three months. Now back to my old glass top. Prefer topless but fund much lass evaporation and less topping off, so that is a plus...
What else is in the tank? Any fish can jump if bullied.
I'm sorry man. That sucks.
Imo a screen doesn't really take away from the top less look. Especially if the tank has a rim. Use 1/4" mesh, it's ideal ime.
The thing about glass tops is they block evaporation so if you use a fan or anything like that over the summer to help with the cooling, they won't work. Also the condensation on them looks annoying and may mess with your light by acting as lenses.
i've never had a cover. Had a pair of clowns for years...rarely did they leave their "spot". Maybe because my tank is 24" deep and for the bulk of time my clowns were the "boss" of the tank. Tang added in later did not mess with them.
How deep is your tank?
That all stated we were recently trying to catch a "problem" fish in the tank and our clownfish launched itself at my wife. My wife says - i could've swore the clown just tried to attack me. A second later the clown launched itself out of the tank and onto the floor. We surmised it did this because we were close to her anemone and she was defending her turf.
a 40B is 17" high - minus whatever substrate you may have. I heard of one vendor that sells a DIY cover - you buy the parts and put the mesh cover together..i'm sure someone will chime in.
http://www.bulkreefsupply.com/diy-aquarium-screen-top-kits-1-4-netting.html
unfortunately it appears to be out of stock...
Bulk reef supply still has the 1/4 inch netting in stock just not the kits. You can always get the rest of what you need from the window screen section in one of the big box stores. Unfortunately they don't carry the clear netting which is what you really want.
I have a small tear in my netting and one of my wrasses managed to find it this weekend. Found him shriveled up on the floor today. Time to order more myself.
I haven't seen it offered in any local stores unfortunately. BRS is your best bet.