An energy-conserving fluid pump is an apparatus used to transport low viscosity fluids like water and fuel without experiencing cavitation, recirculation, nor motor locking while also conserving energy. The apparatus includes a fluid diffuser, a fluid densifier, a convergent housing, and a strut assembly. The fluid diffuser improves the efficiency of the apparatus by expanding the fluid inflow and maintaining a fluid pressure buildup. The fluid densifier shears the incoming fluid flow from the fluid diffuser and increases the fluid outflow pressure. The convergent housing encloses the fluid diffuser and the fluid densifier while facilitating the outflow of the pressurized fluid without the loss of fluid pressure nor cavitation. In addition, the convergent housing facilitates the transfer of torque to the fluid diffuser for the operation of the apparatus. The strut assembly keeps the fluid densifier stationary while enabling the rotation of the convergent housing and/or the fluid diffuser.