Lee's Betta Keepers offer fun and exciting shapes and colors to house your fish in, with a stackable feature to create a beautiful display. Each aquarium comes with a plant and gravel. A feeding hole is located in the middle, and no filtration system is required for maintenance. They are super easy and loads of fun for beginners as well as experienced hobbyists. The Round model holds 40 oz of water without gravel and the Triangular model holds 44 oz without gravel.