Fish have a single circulatory system, while mammals have a double circulatory system. In a double circulatory system, the loop that goes to the lungs is called the Pulmonary Circuit, while the loop that goes to the body is called the Systemic Circuit.

What kind of circulatory system does a fish have?

Fish have a closed circulatory system with a heart that pumps blood around the body in a single loop-from the heart to the gills, from the gills to the rest of the body, and then back to the heart.

Do fish have single or double circulation?

Different organisms have different circulation pathways for blood to travel around the body. ... This is called double circulation. In fish, once the blood leaves the gill capillaries it travels directly to the rest of the body before travelling back to the heart. This is called single circulation.