Globe Grazers on MSN5d
Why Do Fish Swim at the Top of the Tank?
If your fish are spending a lot of time near the surface of the water, it could be normal fishy behavior, or it could be a ...
BBC2mon
Transport of nutrients and water
Fish have a circulatory systems with just one circuit. Their hearts pump oxygen poor blood to their gills, where oxygen is absorbed from the water. The blood then flows around the fish's body and ...