We call them pre-filter sponges. You can either make one or buy one. They not only stop the intake from eating debris but also spread the intake's effective surface area.
This will keep him from sucking up to the filter for naps.
Any store that carries the Fluval Edge should have a small black box in the hanging parts called Pre-Filter Sponge.
Its my favorite one for small filters, I use it on the 92gph walmart $10.00 filters, its only three bucks and they're easy to clean and very effective. You run water through them and squeeze squeeze...
Petco, Petsupermarket, etc.