Common Carp (Cyprinus carpio)
This fish is known as one of the main farmed fish in the world and is widely reared in Europe, Asia and the Far East, and its wild native species is found in the southern waters of the Caspian Sea. Its breeding type is cultivated all over Iran.
Common carp have large scales and continuous dorsal fins. The number of lateral scales in this fish is 30-32. It has forward-protruding mouth. Common carp is distributed in the Caspian Sea basins, Tajan river and all of Iran’s catchment areas. The maximum length of this fish is 150 and the average is 38 cm. The body of this fish is rather long and its length is 3 times of its height. The head of the fish is large and the snout is diminutive. It has a ventral fin. There are 3 to 4 hard needle-like spines on the dorsal fin and 15 (16) to 21 (22) soft and fork-shaped radii. In the anterior fin, 3 hard needle-like spines and 5 or 6 soft and fork-shaped radii can be seen..
This fish is omnivorous and feed of the aquatic microorganisms, worms, crustaceans, baby insects and even animal and plant excrement, animal carcasses, fish eggs and even their babies, in addition to cereal food such as wheat, barley. They eat wheat bran, wheat flour, fish meal, rice bran, tomato pulp, soybean meal, cotton seeds and leftovers.
At temperatures below 7 ° C, they hibernate en masse. This fish lives in fresh water and also loves warm, calm and plant-covered waters.
Temperature and food are effective in carp growth and 20 degrees Celsius is the best temperature for such.
This fish is one of the most important farmed fish in the world due to its rapid growth, the possibility of artificial reproduction, intensive feeding and maintenance and having high resistance to physical and chemical factors of water.

Feeding of common farmed carp
Commonly, the used diet ration should have the right level of nutrients. Here, each component of protein, carbohydrates, fats, energy, vitamins, minerals, and water is called a “nutrient.”
Thus, it is crystal clear that different foods have different nutritional values and differ in terms of nutrients (protein, carbohydrates, fats, etc.), in other words, the percentage of these nutrients in different foods is different and causes that the nutritional value of different foods are different.
The point mentioned above in fish diets is so considerable that the nutritional value of a food item varies for different fish. For example, the rate of decomposition of starch in various cereals is different, and the structure and composition of starch play a very significant role in its nutritional value and digestibility.