The Parts of Koi Fish Body

Koi Fish Eyes:

        The eyes of your koi are located just behind his nostrils. If you examine your fish closely, one of the first things you’ll see is that the fish lacks true eyelids. The covering over Koi fish eyes is really a layer of transparent skin.

        The lenses of its eyes are spherical and rigid. A koi focuses by moving the lens either forward of back within the eye itself.

Koi Fish Gills:

        The fish’s gills allow a fish to breathe underwater. In the koi, you’ll find them behind the eyes in something called the "branchial chambers."

      Covered by a flap of skin and bone known as the operculum, each set of Koi fish gills uses this flap to move water across the feathery organs. The gills contain tissue that possess rich networks of capillary – tiny blood vessels – designed especially for the purpose of gas exchange. Dissolved oxygen is taken from the water and carbon dioxide and ammonia are then released.

Koi Fish Scales:

       And like most fish, koi are endowed with scales. The body of this fish is covered with a host of tiny scales. However, you can find some members of the species where the opposite is true. They’re covered in a small number of larger scales. And don’t be surprised if you encounter an occasional koi with no scales at all. Yes, a few of them really do exist.

        If you were to look at a Koi fish scale under a microscope, the first feature you would notice would be a series of concentric rings. Believe it or not, these rings can help scientists determine the age of the fish – at least it provides them with a rough approximation.

        Very often, a koi’s scales overlap and actually project out of the skin at an angle. They’re also covered with a layer of mucus. This reduces friction as the fish swims. Scales also provide protection from infections – both bacterial and viral – because the mucus covering contains antibodies.

Lateral lines:

        If you examine your koi very closely, you’ll notice a series of very small pores along its sides.  Called lateral line, these pores run midline from its head to its tail.

        Believe it or not, these are another of your fishy friend’s organs of “hearing.” They detect low-frequency vibrations in the water, most notably those that might come from predators.