The present invention relates to fluid pump assemblies in general, and in exemplary embodiments to fluid pump assemblies that are magnetically supported in position, and to related kits and methods useful to circulate water in aquariums. The fluid pump assembly comprises an outer mount, an inner mount, and a pump. The outer mount includes at least one outer permanent magnet; the inner mount includes at least one inner permanent magnet; and the pump includes at least one soft magnetic material. The outer permanent magnet, the inner permanent magnet, and the soft magnetic material collectively form a magnetic circuit.