1/4" screen netting, as I've seen a few fish still fit through eggcrate.given how important it is to have a secure top, what do people do when they have an over the top return, an auto feeder, and wires that need to come from the tank? Are people able to make more custom tops that cut out the space needed?
I have a corner overflow, so inverted the corner where the overflow is at, and run any cords to the overflow, so they don't raise the top.
An auto feeder will drop food through the screen.