Clay pots ????
 

How do you make the holes??? What kind of tools do you need?

A bucket of water, a screwdriver or chisel, a pencil, and a hammer.

Soften up the pots by placing it in the water, then after 6-8 hours take it out, take a pencil and mark where you want to cut. Take your chisel and place on the pencil line and tap until you go throughand you keep going until you crack the pot.

Hope this helps,
Dan

P.S. Make sure you can't see any pencil lines before placing in your aquarium.