Do fishes there an open or closed circulatory system? How many chambers does a fish heart have? How does blood flow all through the fish body?

As in every vertebrate the circulatory system of fishes is stopped, i.e., blood flows only within blood vessels.

The fish heart has only two consecutive chambers: a thin-walled atrium and a muscular ventricle. The arterial (oxygenated) blood comes from the gills and gains arteries towards tissues, and then venous blood is collected by veins and reaches the atrium of the heart passing to the ventricle that pumps the venous blood in the direction of the gills to be again oxygenated.