Koi Anatomy

Barbels: These are the soft fleshy projections located on either side of a Koi's mouth. All koi have two pairs, the larger pair being located below the smaller pair. The barbells contain taste buds used to help the koi find food.

Fins: Koi have a total of seven fins: paired pectoral find, paired pelvic fins, and a single anal, and dorsal fin. Fins are used for both locomotion and directional swimming.

Swim Bladder:: The swim bladder is part of the gastrointestinal tract and koi maintain a direct connection from the esophagus to the swim bladder in the form of the pneumatic duct. The swim bladder allows the koi to achieve neutral buoyancy.

Stomach: Koi have a relatively long, coiled intestinal tract instead of a stomach. Food is ground by the pharyngeal teeth against the carp stone and then digested as it passes through the intestine, the rectum, ends at the vent where products are released into the water as waste.

Pharyngeal teeth: Koi have a set of teeth in their throat that grind food against a dental pad called the "carp stone." These pharyngeal teeth help in the process of digestion.

Nostril: Koi have a pair of nostrils near the front of their head. These nostrils allow water to pass into and out of the nasal organs that are used for smell for aqueous odors.

Scales: Scales are thin bony protective plate structures that are part of the dermis (skin layer) which cover the body of the fish to provide a flexible protective coating. They possess microscopic growth rings similar to a tree trunk, by counting these ring it can be used to determine the age of the scales on the fish.

Mucus: Mucus is protein excreted by the fish for their lines of defenses against the entry of disease-causing organisms, together with the scales and skin. It is essential for the health of the fish that these layers of protection remain undamaged.