FEEDING THE FISH

Different fish prefer different types of food. Fish in ponds can be fed in many ways shown below:

  1. Feeding by fertilizing the pond
  2. Feeding the fish on large plant materials
  3. Feeding the fish on other fish
  4. Feeding Fish on Artificial Feed

 

Feeding fish by fertilizing the pond.

Pond fertilization is the cheapest way of feeding fish. The entire process of pond fertilization has been described in sub-section 4.3. However, the production of natural food through fertilization is usually limited by the environment. Production of fish by fertilization only is low (maximum 0.3 kg/m2 per year). This low production can only be fit for subsistence purposes and for household nutrition.

Feeding fish on larger plant materials

Among the farmed fish it is mainly Tilapia zillii that feeds effectively on larger plant materials. However, the plant materials must be soft. The easiest way to feed fish that feeds on larger plant materials is to plant vegetables in the dyke space around the pond (see figure 4.21). The younger, softer plant parts are harvested from the garden and placed in the pond.

Feeding fish on other fish

This case so far occurs only in the farming of the African catfish (“mmale”), which is a predator. The easiest way to feed such predators is by stocking the predator (“mmale”) together with a large quantity of the prey fish (Nile tilapia). The prey fish should be stocked at a larger size than the predator so that they are not eaten. They are then able to continuously reproduce juveniles for the “mmale” to feed on.

In that case, the pond should also be fertilized for the Tilapia.

For commercial production of more than 0.5 kg/m2 per year, the farmer must provide good quality feeds either to supplement the fertilization or as the only source of feed. Feeding is more expensive than fertilizing a fish pond. Therefore, it is only economic to feed fish with expensive feed if the farmer is producing intensively for markets that offer good price for fish.

The higher the market price of fish, the more the farmer can afford to feed fish with expensive feed.

For middle level of production and fish price, the farmer should use limited quantities of the expensive feed only to supplement fertilization.

The nutrients obtained from feed

Like all other animals and humans, fish requires the following nutrients for the purposes indicated

The different nutrients and their purposes

Nutrient Purpose
Protein •      Body building
Fats (lipids) •      Energy

•      Proper functioning of the body

Starch •      Source of energy
Minerals •      Body structure

•      Normal functioning of the body

Vitamins •      Protect the fish from diseases

The common sources of these nutrients

The feeds must be good quality but at the same time not too expensive. Therefore, the sources of the nutrients should be cheap and easily available. Sources of nutrient for making feeds are called “feed ingredients”

The common local sources of important nutrients for fish feeds are mainly agricultural wastes, agricultural by-products, feed processing by-products or by-products from slaughter houses.

The different nutrients and their local sources. 

Nutrient Sources Nutrient Sources
Protein Mukene, Dried blood meal, sunflower cake

Soya oil cake

Cotton seed cake

Minerals Wheat bran Crushed egg shells Crushed snail shells

Shops selling animal feeds

Fats Mukene sunflower cake Simsim cake

Cotton seed cake, Rice bran Soya oil cake

Vitamins Shops selling agricultural supplies

Shops selling animal feeds Available in green plants in fertilized ponds

The nutritional requirements of fish 

The requirements of each of the nutrients by fish as percentages of the total feed varies from fish type to fish type (see table 4.5), It is also different for the different ages of each fish. In general the nutritional requirements are as follows.

The requirements of different nutrients by fish at different growth stages

Nutrient Fry Juvenile Grower Broodstock
Protein 42-39% 37% 35% 37%
Fats < 8% < 8% 6% 5%
Starch 25% 25% 25% 25%
Mineral 1-3% 1-3% 1-3% 1-3%
Vitamin < 1% < 1% <1% <1%

How to make home-made fish feed

The following food combinations using the above ingredients have produced good growth.

One way a fish feed can be made from ingredients

Ingredient The number of cups of each ingredient to make 100 cups of feed
Mukene 40
Maize bran 40
Cassava 9
Sunflower cake 9.5
Vitamin pre-mix (poultry) 0.5
Shells 1

In areas where some of these ingredients are not available, there may be alternatives.

e.g. Cotton seed cake may replace sunflower cake, Wheat bran or rice bran can replace maize bran, where religion is not offended, blood meal can partly replace some of mukene.

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