Updated September 2018
Unlike humans fish breathe in water.
Why? Because water is the easiest way of delivering air to them.
So do goldfish, or fish in general, breathe air? Yes, but not directly into the lungs as mammals do (except for some tropical fish. They breathe oxygen not air.)
Gills in fish are the same as lungs in humans.
- Gills contain a network of fine blood vessels (capillaries) that take up the oxygen and diffuse it through the membranes.
- As water passes over the network of fine blood vessels contained within the extremely fine filaments of the gills, fish absorb the water’s oxygen content.
The Necessity of Air
All living creatures need fresh air to survive and that’s why your aquarium has to be connected to a reliable source of air to ensure the water is oxygenated regularly.
Fish get their supply of oxygen by breathing the water that’s in the aquarium.
We advise you to install an air hose because the fish will suffocate without oxygen. If no one stays in your home during the day, consider connecting the air hose to a pump so that the fish get their fresh supply of air from the pump.
Some types of fish such as the goldfish are able to jump above the water line. Normally they do this to get air. If they’re jumping like this it means t