An indoor fish tank has a of walls and bottoms interconnected to define distinct fish holding, sedimentation and bioreactor sections. Water flows out of the bioreactor section into the top of the fish holding section, and then from the bottom of the fish holding section into the sedimentation section. A frame structure with braces connected with the tank walls and bottoms supports the tank on a ground support, with at least the bottom of the fish holding section raised above the ground surface.