Culture of fish food organisms

Unit 1 - Introduction

1.1.Introduction to Fish food organisms
Fish food organisms are microscopic organisms naturally present in the aquatic environment as primary food for the larvae of fin fish and shell fish. Their size ranges from a micron to few millimetres. They are tiny forms which suits the mouth size of all kinds of fin fish and shell fish larvae. Eggs feed on yolk to become larvae. In the transitional phase from eggs to larvae they are delicate, they shift in size, gut changes along with digestive apparatus. Much of their protein digestion takes place in the hind gut epithelial cells. To overcome this fish food organisms play a vital role. The major expansion of finfish and shell fish aquaculture around the world is attributed to the development of standard mass production techniques of live feed. Live feeds are able to swim in water column and are thus constantly available to the larvae.Fish food organisms are mainly divided into protozoans, bacteria, phytoplankton, zooplanktons crustaceans and worms. These fish food organisms are cultured based on their biology, reproduction and ecology, nutrition and water requirements. They are obtained by the use of chemical fertilizers, cattle or poultry manure and vermicompost.