Abstract: Our invention is called WindowQuarium™, which is a weather-resistant enclosure that gets inserted and secured into a window frame, allowing an aquarium or terrarium tank to be installed and operated, eliminating the need for any stand or cabinet to hold the tank, and without occupying any square footage within the room. The design of the enclosure prevents additional sunlight from creating algae, and the combination of materials plus the air plenum and grill vents in the base allow internal air to flow into and around the enclosure and the accompanying aquarium tank, allowing the temperature of the tank to remain stable.