Feeding of Fry and fingerling
Artemia is the best starter food for fries. Artemia is a natural type of zooplankton, which is shipped in cans. The encapsulated cysts are hatched and then live Artemia are put in the tank and preyed upon by the young larvae and fry. It is recommended to feed the fry frequently in the first period of rearing.
A table showing how fries are fed:
|Fish age||Average weight||Crumble size|
|7-14||0.05 – 0.10||0.2mm|
|14-21||0.10 – 0.015||0.3 – 05 mm|
|21-28||0.15 – 0.30||03. – 05 mm|
|28-35||0.30 – 0.50||0.5 – 0.8 mm|
|35-42||0.50 – 1.5||0.5 – 0.8 mm|
|42-49||1.5 – 3.0||0.8 – 1.2 mm|
|49-56||3.0 – 50||1.2 – 1.5 mm|
MANAGEMENT OF FRIES AND FINGERLING
Daily Schedules Of Works In Rearing Of Fries
|6 am||Rubbing the bottom and sides of trays gently with palm and siphoning of feces and feed.|
|8 am||Flow the water in the pond and replace at the same time of flow, this is done gradually to avoid stressing the fries|
|9 am||Feeding and Formalin treatment.|
|1 pm||Antibiotic treatment if necessary|
|4 pm||Siphoning and feeding.|
|7 pm||Siphoning, rubbing the surface of the tray, flowing water, and feeding.|
|10 pm.||Formalin Treatment. Antibiotic|
SORTING: A Necessary Factor
Catfish grow differentially as a result of variations in the genetic quality of the fish species. Fish start to have their varied genetic quality from the egg stage (from different egg sizes). Therefore, the differential growth pattern becomes evident. This phenomenon, which causes the emergence of oversized fish (SHOOTERS), can cause cannibalism. The situation can thus, be well managed by sorting out the shooter (every two weeks) into another pond and this is where the extra tank is needed.
The following are used to sort fish:
1. Counting board
2. Sieve with lager opening, depending on the size of the fish (sorting bowl)
DISEASES OF FINGERLINGS
Usually, no disease breaks out during pond nursing of fries if the pond preparation for nursing is carried out according to the above suggestions. As a result of high temperatures and the abundance of natural food organisms, the resistance of growing fish is excellent.
Bacterial infection of the fish population reared in hatcheries is quite common. The most frequent pathogen is Flexibacter columnaries. Fish reared in overstocked conditions or in tanks with insufficient cleaning and also the starving fish populations are susceptible to such types of bacterial infection. Colour of infected fish is whitish. Bacterial colonies can develop mainly on the epithelium of fins and barbells and around the mouth of the fry. Sometimes small pieces of sick fish are curved backward. Infected fish stay sometimes in a vertical position “hanging” near the surface of the water.
After the outbreak of the disease same antibiotic and formalin treatments with higher frequency are required than for prophylaxis. Fungal and parasitic infections may occur among the different sizes of fry and fingerlings. Malachite green, Formalin, or Dip Terex baths are the best measures to control them. The suggested concentration of malachite green treatment is a maximum of 0.07 mg/liter. The frequency of their fatigue treatment is 4-5/day. Formalin is a good tool for controlling bacterial and protozoan infections at the rate of 5-10 ml/100 liter applied as it was detailed before. The suggested frequency of formalin baths is effective against worm-type gill or skin parasites. The allowed frequency of such treatment is not more than two-type gill or skin parasites. The allowed frequency of such treatment is not more than two-three days.
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