There are three types of food used in aquaculture:
1. Natural food occurs naturally in fish ponds. This includes detritus, bacteria, plankton, worms, insects, snails, aquatic plants and fish. Their occurrence and abundance depends on the water quality and in particular fertilization.
2. Supplementary feeds usually consist of feed materials available locally such as terrestrial plants or agricultural by-products like wheat bran.
Many kinds of feed materials may be used as supplementary feeds for your fish such as:
- Terrestrial plants: grasses, leaves (e.g. cassava)and seeds of leguminous shrubs and trees/vegetables;
- Aquatic plants: water hyacinth, water lettuce, duckweed;
- Small terrestrial animals: earthworms, termites, snails;
- Aquatic animals: trash fish;
- Rice: broken, bran, hulls;
- Wheat: middling, bran;
- Maize: gluten feed, gluten meal;
- Oil/cakes after extraction of oil from seeds of mustard, coconut, groundnut, cotton, sunflower, soybean;
- Brewers wastes and yeast;
- Slaughterhouse wastes: offal, blood, rumen contents;
- Manure: chicken droppings, pig manure
Supplementary feeds are available in two forms
i). Dry feedstuffs such as cereals and cakes with about 10% moisture. These are easier to transport, store, and to distribute to the fish.
ii). Wet feedstuffs such as waste blood, rumen contents, molasses and brewery wastes with 30 to 50% moisture. Moist feeds do not keep well, and only small quantities should be prepared at a time. These feeds require special treatment, for example mixing with dry feedstuffs to absorb part of the moisture or drying to improve storage life before feeding.
3. Complete feeds: Are made from selected ingredients to provide all the nutrients necessary for the fish to grow. Under intensive systems, feed provided to the fish must meet all their dietary requirements. The fish rely wholly on exogenous feeds. The feeds must be complete in terms of nutrients supply.
It is important to note that:
i). Small fish need more food than larger ones.
ii). Where there is plenty of natural food, less supplementary feed should be used
iii). Where low stocking densities are used, less supplementary feeds are used
iv). The better the quality of the feed (low FCR), the less the quantity needed to feed the fish
v). More food is required in warm water than in cooler water.
vi). It is therefore recommended for producers to constantly adjust the feeding throughout the production cycle for better results.
vii). FCR will be affected by Overfeeding, poor feeds, poor pond fertilisation for semi intensive production and poor fish health.
How to feed:
For most fish, feeding twice a day is sufficient - at about 10 am and 4 pm. Earlier than 10 am in the morning, the water is a bit cold and oxygen levels are low so this is not a good time to feed the fish.
If you feed at close to the same time and at the same place in the pond every day, the fish will learn to come for the feed.
Recommended feeding rates for tilapia or tilapia/clarias in Polyculture:
|Approx month after stocking||Assumed size of fish||Amount of wheat bran per day||Pelletted diet(26% protein)|
|1-2||5-20g||1 g/fish||1 g/fish|
|2-3||20-50g||1-3 g/fish||1-2 g/fish|
|3-5||50-100g||3 g/fish||2 g/fish|
|5-8||100-200g||4 g/fish||3 g/fish|