Final answer:
The amphibians and some reptiles, not fishes, have a three-chambered heart and a double circulatory system, whereas fishes have a two-chambered heart.
Step-by-step explanation:
The group of fishes that typically has a three-chambered heart and a double circulatory system are not fishes, but rather amphibians and some reptiles. Contrary to this group, actual fish possess a two-chambered heart. In amphibians, the heart consists of two atria and one ventricle, and the circulation is double: one circuit for oxygenating blood through the lungs and skin, and another to carry oxygenated blood to the rest of the body. While the heart of amphibians does allow for some mixing of oxygenated and deoxygenated blood, the system's design helps maintain higher pressure in the blood vessels that are responsible for transporting blood both to the lungs and throughout the body. This is significantly different from the hearts of mammals and birds, which have a four-chambered heart that completely separates oxygenated and deoxygenated blood, thereby preventing any mixing and increasing the efficiency of the circulatory system.