there is alot of ways to cover it up. glass,plastic,egg crate,duck tape, screen, many many more. but for me , my tanks are topless no lids or anything , just an open top the way i like it so i can view from the top. what i did tho is i leave 3 inches of water off before the tanks top rim. so my tank is not full to the top.also i keep them happy with losts of caves and underground tunnels. i had my eels now for a year and a half and not 1 has jumped out.. it has worked for me it might not work for u tho. just a friendly warning. Good luck.