My other sister wants to use this for a fish bowl. It's about 4 gallons. I'm kinda afraid to fill it up with water because the small base looks fairly weak but that's the only way to test it to be sure it'll hold the weight of the water + gravel. :-\
She wants to fill 3/4 of it with water and about 1" of gravel. The PepsI can is for size reference.