Desirable characteristics of fish for culture

a. Growth rate:

• Must have a natural ability to grow fast so that they attain a marketable size in a shorter time.
• Small fish species aren’t suitable for commercial purposes even if they have other good characteristics.

b. Efficient conversion of food:

• The species of fish that will give more edible flesh per unit of food consumed is preferred over that which gives less flesh per unit weight.
• Some parameters related to feed conversion are:

Food conversion ratio (FCR) = Feed intake (Kg)/ Weight gain (Kg)

Feed efficiency ( %) = Weight gain (Kg)/ Feed intake ( Kg) x 100

c. Short food chain:

• This will reduce the loss of energy resulting from the passage of one link of production to the next for the production of low-priced products.
• Carnivorous species generally need a high-protein diet and are therefore considered to be more expensive to produce.
• Eg: Short food chain ( Silver carp, Big head carp, Tilapia) and Long food chain ( Rainbow trout, catfishes).

d. Ready to accept formulated feed:

• To obtain a high production rate, reared fish must accept an abundance of cheap, formulated feed.
• Larvae that accept formulated feeds would be easier to rear in hatcheries.

e. Disease and poor water quality resistance:

• The ideal cultured fish must have low disease susceptibility, especially in cultured regions where knowledge of pathogens is limited, or where therapeutics are unavailable or expensive.
• Reared fish must be resistant to disease, tolerant to a wide range of environmental patterns like low D/O, high ammonia, a wide range of temperature and pH, etc., and accept handling and transport without difficulty.

f. Meat quality/ Consumer’s acceptance:

• Nepalese people prefer carp whereas Americans prefer catfish.
• Similarly, milk is highly liked by Southeast Asian countries but not by Kenya.
• Certain catfish introduced into Europe that breed and grow easily in ponds are considered most unsuitable because consumers don’t like them.

g. Easy to breed in captivity:

• To ensure an easy and constant supply of fish seed for rearing, it is best if the fish reproduce in captivity.
• A fish that doesn’t fulfill this condition can’t be domesticated.

h. High fecundity:

• Fecundity refers to the number of eggs in the ovary of females before the spawning period.
• A shorter incubation period and larval cycle often contribute to lower mortality of larvae and greater survival in hatcheries.
• Fecundity is calculated as absolute fecundity and relative fecundity.

i. Economic and market consideration:

• Must be Economically viable and easy to market.
• Besides these, scale-less carp, and reduced vertebrate bone in different carps, colors, etc. are also preferred. Eg: Chinese and Indigenous major carp.