Physics of domain walls and bubble nucleation is important especially in view of applications to the early universe and production of gravitational waves. I demonstrate that domain walls and their movement for a class of strongly coupled theories can be described in terms of a simple four dimensional "extended" hydrodynamic model. This model puts together perfect fluid description of the strongly coupled fluid with additional scalar field which is active near the domain wall. I go on analyzing the velocity of the moving domain wall, which is usually challenging and thought to incorporate out-of-equilibrium physics. I obtain a simple formula for the velocity essentially in terms of the equation of state and perfect fluid hydrodynamics.