I have a fine mesh screen that sits over the top of the tank under the hood that houses the lights, he has managed to push the screen up and squeeze under the space in the hood where the wires go. The hood is far to heavy for the cat to have lifted it! I have now bought a piece of perspex to sit ontop of the screen to avoid any further escapes! The last thing I want is any harm coming to my wee guy! Houdini is the master of escapology....hence the name! He escaped certain death travelling here as a stowaway in a jet engine...then escaped from a temporary tank I had him in on the first night he was here. Hopefully there will be no more escapes now!