Oxygen in the water moves into a fish's blood via their gills. Fish have a single circulatory system.

The regions of the heart form an S-shaped loop, to fit into pericardial cavity. The heart of the fish contains completely deoxygenated blood and has a single circulatory system.

A study has shown that marine life around the world is surprisingly dependent on a single ocean circulation pattern in the Southern Hemisphere where nutrient-rich water rises from the deep and ...

Why Water Circulation Matters for Aquarium Health When you think about what keeps an aquarium thriving, water circulation might not be the first thing that comes to mind—but it should be ...

A study has shown that marine life around the world is surprisingly dependent on a single ocean circulation pattern in the Southern Hemisphere where nutrient-rich water rises from the deep and ...