How do goldfish breath underwater?

Fish have special body parts called gills that help them breathe underwater. Gills are thin, feathery structures that are located on either side of a fish's head. Inside the gills, there are tiny blood vessels that absorb oxygen from the water. Fish breathe by taking in water through their mouths and passing it over their gills. As the water passes over the gills, the oxygen in the water is absorbed into the bloodstream. The fish then expels the water out through their gills.

In the case of goldfish, they do not have gills, but rather they have a special organ called a labyrinth organ or suprabranchial organ. This organ is a modified gill that has a large surface area and is lined with many blood vessels. The labyrinth organ allows goldfish to breathe air from the surface of the water. They have a special organ that helps them process air from the surface of the water.