Abstract: An aquarium-maintenance system has a transparent filtering canister (1) with quick-joint inlet attachment (3) and quick-joint outlet attachment (8) to transparent aquarium tubing (5, 13) together with a handle (14) to allow quick, convenient and clean replacement and/or back-flow cleaning of filtering members (11). A system pump (12) has variable output capacity for filtered water circulation and optionally for aquarium flushing with a cannister bypass (19), discharge conveyance (21) to a drain-water disposer (22), refill conveyance (24) from a refill-water source (23) and back-flow conveyance (16) from a wash-water source (17). This is a comprehensive aquarium-maintenance system that is adaptable totally or in part to all sizes and types of aquariums (6).