Fish Tank Plug (National geographic Half moon aquarium)

This is a plug to cover the hole of the National Geographic aquarium. I believe I have the 1.2 gallon model. My toddler son decided that the fish was hungry for grapes so I printed this to plug the hole. Hopefully the temptation is gone now that there is a plug, but we shall see. I am also thinking of adding threads to it to make it get stuck.