Aquaculture Feed and Fertilizer Resources Information System

Grass carp - Ctenopharyngodon idellus

(Valenciennes, 1844) [Cyprinidae]

FAO official common names: Fr - Carpe herbivore; Es - Carpa china

Taxonomic and biological features:

Distinguishing characters
Light yellow body, grey-green back, grey abdomen. Dark green dorsal and pectoral fins, other fins light grey. Body of adult fish elongate and sub-cylindrical (length 3.5-4.8 times body height) (Figure 1). Abdomen round with no ridge. Head is compressed and slightly pointed and mouth terminal. Inter-orbital broad and ridged. Eyes small. Snout blunt and the mouth is terminal, lower jaw shorter than upper jaw. Gill membrane connected to the isthmus. The dorsal fin (iii, 7-8) short and originates slightly in front of pelvics. Lateral line is straight with 37-42 large scales. Anal fin (iii, 8). Vertebrae 39-42. Gill rakers (21-25 inner) are short and stick-shaped. Pharyngeal teeth are pectinate. Swim bladder large with two parts (Ni and Wang, 1999). Larvae with asteroidal strip from head to tail (black strip) (Ni and Wang, 1999).

Gonadal maturation occurs in still waters. Spawning associated with rising water levels and occurs in running water and eggs are pelagic. Grass carp mature at 3 to 4 years in southern China, at 4 to 5 years in the Yangtze basin, and at 5 to 6 years in northern China. Males normally mature one year earlier than females. Body weight at maturity is around 3-8 kg. The optimal water temperature for reproduction is 20-25 °C. Egg diameter is approximately 1.5 mm (Ni and Wang, 1999). Total fecundity of grass carp at different ages is shown in Table 1 (China National Standard for Grass carp, GB 17715 -1999). Larval growth is temperature dependent. At 24°C larvae reach 10.5 mm after 5 days and at 25°C attain 12.4 mm. At 30oC the fry can reach 18.0-23.4 mm after 15-21 days (Ni and Wang, 1999).