Abstract: A centrifugal pump, particularly for fountains and aquariums, for which an electric motor and a pump are disposed coaxially to one another, the electric motor being constructed as a single-phase synchronous motor with a permanent magnet rotor and connected with an open impeller of the pump with impeller blades, which are bent back from a hub towards the outside spirally with respect to a specified direction of rotation, is improved in the direction of a simple and inexpensive production as well as a compact and robust construction without a significant loss in overall efficiency owing to the fact that the impeller blades are constructed flexibly in such a manner that, if the synchronous motor starts counter to the specified direction of rotation, they are propped open by at least 2% in the radial length.