Chinese Fish Culture. Natural Food of Fresh Water Fishes,

The growth rate of fish depends on the amount of food available and its nutritive value. In addition, different fish feed on different food. For instance, grass carp feed on various terrestrial and aquatic plants white bighead feed on phytoplankton and striped bighead feed on zooplankton. Generally fish are grouped as either herbivores, carnivores or omnivores. However, during young stages, most fish eat plankton. Natural fish food is generally comprised of phytoplankton, zooplankton, benthic animals, aquatic plants, and dead animals and attached bacteria. The type and quantity of natural fish food fluctuates seasonally and varies according to the type of water body. Physical, chemical and biological factors also affect the growth and development of organisms in a body of water. Physical factors vary seasonally and according to the geography and, in turn, affect the chemical and biological factors. The major physical factors are temperature, water current and light. The major chemical factors are organic matter, dissolved inorganic salts, dissolved gases and Ph. The biological factors refer to the interrelationships among species.