Koi carp, a scientific study

Koi carp, a scientific study
Cyprinus Carpio Linne
with dissections of Koi and common carps

Science in winter is just perfect, especially when the clouds are in the sky and threatens rain and makes things cold. Today we are going to study the Koi carp and the common carp. “I love science,” Adhijaya said when he learned that we were going to do some experiments.

The Koi carp was beautiful and orange. Pallav sir had brought it from Lagankhel. He had also brought a nice sized common carp. While we were going to study the Koi carp mostly, we were also going to dissect the common carp.

To begin with, we did a physiological study of the carps. There were two groups. Srijana ma’am took the smaller young: Kashi, Nirousha, Khayanna and Shourit. After the children had looked at the Koi carp, she had them sitting down and making artwork of studying the common carp as it was slightly bigger. Its scales were big and it was beautiful!

Sabina ma’am took over the older young: Shila, Vidheha, Anusha, Shuvam, Adhijay, Bishes. They too made artwork but Shila was busy with photography and supporting the learning. Anita didi was busy turning the research material into a readable hand out.

Once the study and the artwork was over, little 14 month old Zoya also came and we gathered around the table and started the dissection. First Pallav Sir again showed Koi has scales, skin, fins, operculum (gill cover), eyes, nostrils, barbels and lateral lines.

Pectoral, ventral, dorsal, caudal and anal fins help the fish move, he said. Pectoral and ventral fins are like hands and legs! A fin has bone-like spine, soft filament and membrane. The fin grows back if it is cut or damaged.

The barbels (which are like moustaches) help with taste as koi carp are bottom feeders that also eat food that floats. It is omnivorous. Koi carp has three rows of teeth in its neck and not in the mouth, funny! They filter plankton from water. Lateral lines are scales along the side from head to tail. They help hear the sounds. Five pairs of Saiko in the gills help the koi carp breathe.

The kois skin secretes mucus on the body which prevents parasites like worms from sticking and disease causing animals and plants. It also helps the fish swims. Koi carp is colourful because of four kinds of pigment cells. They react to light.

The scales form a circle that increase in numbers as the koi grows older. Counting the circles can help us tell the age of the koi carp. The koi does not have a stomach and the esophagus is joined with the intestines. The fatter intestine secretes the digestive fluid. They have one organ that does the work of the liver and the pancreas. The green gallbladder is connected to the liver. It has air bladder has two bubbles. The heart has pericardium, atrium, ventricle, and artery.

Anus is attached to the rectum, ureter and gonads. Gonads make sperm or ova. Koi carp lives in fresh water that is 8 to 30 degrees Centigrade. If the koi looks white, it is probably cold. Under 7 degrees, the koi carp hibernates and dies below 2 to 3 degrees.

 Koi carp eats insects, shellfish and plants. It eats everything twice, first swallowing it, then disgorges what is has swallowed when it is free and chews the food with the teeth it its neck. It lays 200,000 to 400,000 eggs that are externally fertilized and hatch average four days later. A koi carp usually lives for 70 years.