Fish Nutrition And Feed Management

Fish Nutrition

Fish Nutrition And Feed Management

Natural fish food organism or Live food organisms

  • A variety of natural fish food organisms are found in a water body
  • The natural food provides the constituents of a complete and balanced diet
  • Natural feeds have high protein and fat contents, which promote the growth of the fish. 

Herbivorous fishes: They feed on plant material, which forms more than 75% of gut contents.

Omnivorous fishes: They consume both plant and animal food. Carnivorous fishes: They feed on animal food, which comprises of more than 80% of the diet.

Herbivores are divided into 2 sub-groups.

Planktophagous fishes : They consume only phyto- and zooplankton

Detritophagous fishes : They feed on detritus.

A wide variety of ingredients are available for use in fish feeds

1. Grasses
2. Pulses and Legumes
3. Miscellaneous fodder plants crop
4. Fruits and vegetables
5. Root crops
6. Cereals
7. Oil-bearing seeds and oil cakes
8. Animal products
9. Miscellaneous feed stuff
10. Additives


• Fish production in a waterbody is directly or indirectly dependant on the abundance of plankton.

• Planktons are free floating organisms found in water


  • Phytoplankton gives green colour to the water due to the presence of
  • chlorophyll.
  • Phytoplankton occupy the base of the food chain and produce
  • phytoplankton consist of three major classes:

A. Chlorophyceae

B. Cyanophyceae

C. Bacillariophyceae

A. Chlorophyceae

• These are called green algae due to the presence of chlorophyll.

• Many chlorophyceae members are useful as food to fishes.

B. Cyanophyceae

• These are also called as myxophyceae

• commonly known as blue green algae

• This colour is due chlorophyll a. carotenoids and biliproteins

C. Bacillariophyceae

• These are called diatoms

• They are unicellular organisms with different shapes and sizes.

• These may be yellow or golden brown or olive green in colour


Plankton consisting of animals is called zooplankton The zooplankton forms an important group as it occupies an intermediate position in the food web




Bioenriched feeds

  • Process involved in improving the nutritional status of live feed
  • By feeding or incorporating within them various kinds of materials such as Microdiets
  • Microencapsulated diets
  • Genetically engineered baker’s yeast
  • Emulsified lipids rich in w3HUFA (Highly Unsaturated Fatty Acid) together with fat soluble vitamins.

Prepared (artificial) Diets

Artificial diets may be either complete or supplemental

Complete diets supply all the ingredients:

  • Protein
  • Carbohydrates
  • Fats
  • Vitamins
  • minerals

Protein levels in aquaculture feeds generally average:

18-20%- for marine shrimp

28-32%- for catfish

32-38% -for tilapia

38-42%- for sea bass

30-40%- for carp fishes

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