Planaria trap for fish tank

planarian trap for a fish tank, This size is suitable for al fish tanks however I would recommend scaling down to 85% if you have small shrimp due to the size of the holes. simply put bait in the middle screw it up and throw it in the tank. ive set it to max walls so its solid to help it sink, you can change this and do a lot less and place a rock on top if you wish.