A corner bracket, a frame assembly using corner brackets, and an aquarium utilizing the frame assembly are disclosed. The corner bracket includes a hollow base member having first and second hollow coupling members projecting outward therefrom. The first and second hollow coupling members are used to secure hollow frame members together using an expandable adhesive. Four hollow frame members and four corner brackets can form a frame assembly, typically having a rectangular configuration. The frame assembly supports a pair of doors, each enclosed by a door frame, which can slide back and forth on the frame assembly. The frame assembly can be secured to both a front wall and to a pair of sidewalls of an enclosure having an open top. A cover can close the open top to form an aquarium for amphibians.