(Photo by Julie Charlier from Exterior Concepts Holding Pond)
Five Senses of Koi:
Those whiskers are called barbels and koi have them to help taste. In a way, they are similar to your tongue, as they have taste buds on them. Many, many years ago, koi had three barbels, but now they only have two. Koi also have taste buds on their mouth and lips, so they have an excellent sense of taste.
Koi do have a very good sense of smell. Their extremely acute sense of smell and their sense of taste are their primary senses in finding food in their natural environment. When food dissolves in water it can then be detected by their nose, with the nares that are located at the base of their nostrils. The nares can be thought of as U-tubes, as the water enters through the forward opening and exits through the rear opening. Water does not flow to any other part of the body from the nares.
Yes, koi do hear, even though they have no external ears. This is accomplished by the koi sensing vibrations in the water. Koi hear with what is called the Weberian Ossicles, a group of bones that are connected to one end to the forward swim bladder and on the other end to the auditory center, a sensing organ that resembles our inner ear. Koi, like other fish, are very sensitive to sound and can be stressed to the point of becoming ill by loud noises, especially on a constantly recurring basis.
Koi see exceptionally well. They have such good sight they could probably even read a book. They actually have a greater range of vision than we do, as they have bilaterally placed eyes that are independently moveable. They also see color and black and white. The eyes of the koi are more vulnerable than our eyes because they do not have eyelids; so, great care must be taken when they are netted and handled.
The most sensitive area for this sense is located about midway down the side of the fish, called the lateral line. Holes in the scales lead to a canal beneath the surface that contain neuromast cells. Water movement in any direction striking the sides of the fish will cause the mucous in the canal to vibrate. These vibrations stimulate the cells that are linked to the nerve system and provide koi with one of the most effective survival techniques (flight reaction).
Originally published in Portland Japanese Garden’s Member Newsletter, July 2013