Abstract: A modular animal habitat includes at least one vertical stack of similar compartment units formed of a transparent plastic, each unit including a rectangular bottom wall and front rear and end walls projecting upwardly from the bottom wall borders and terminating in coplanar flanges. Each unit rests on an underlying unit and has depending tongues engaging the inside faces of the underlying unit front and rear wall. The end walls of each unit have circular ports and an internally ribbed conduit network extends vertically along each end of the stack and is formed of tubular tees whose cross arms are coaxial and separably joined end to end and radial legs of alternate tees are coupled to the ports in successive units. Representations are applied to the unit walls by decacomania and the top unit is closed by a roof cover. Transversely offset habitat stacks may be coupled by the conduit network. Each tee is formed of mating halves separably interlocked by retainer rings.

Abstract: An electrically driven pump (10) for circulating liquid in a fish tank (16) or the like comprises a stator (32); an impeller-rotor assembly (80) comprising a shaft (82), a magnetic rotor (84) mounted on the shaft (82) for rotation in response to the electromagnetic field produced by the stator (32), and an impeller (100) rotatable with the rotor (84); and a housing (50, 60) disposed adjacent the stator (32) and defining a chamber for supporting the impeller-rotor assembly (80), the housing having inlet (44) and outlet (70) openings, one of the openings (70) being spaced from one end of the impeller-rotor assembly (80), the housing (50, 60) also defining a connecting channel (66) communicating the one opening (70) with the one end of the assembly (80) for bathing the one end of the assembly (80) in liquid.

Abstract: A novel filter assembly (10) and filter cartridge (12) therefor for use in an under-gravel filtration system in an aquarium tank (24). The filter assembly (10) includes an airlift tube (14), a filter cartridge (12) removably secured to the upper end of the airlift tube (14), and a tubular member (16) extending through the filter cartridge (12) and into the airlift tube (14). An aerator (18) disposed near the bottom of the airlift tube (14) is connected to the tubular member (16) by air tubing (19, 20). The top and bottom walls (48, 50) of the filter cartridge (12) are apertured (56, 58). When air is forced down the tubular member (16) and out the aerator (18), the rising air bubbles in the airlift tube (14) draw water up the airlift tube (14) and into the filter cartridge (12) through the openings (58) in the bottom wall (50), the water being returned to the aquarium tank (24) through the openings (56) in the top wall (48).