What is a good quality fingerling/Fry?
A good fish fingerling is that which will produce the most profitable harvest at the shortest possible time. The following are the qualities of good fingerling:
- Fish will grow fast and reach market size quickly
- Fish gains the largest weight for every weight of feed given
- Fingerlings that is composed of only the fish type popular in the market, not mixed.
- All the fish, and not only some, will grow at about the same pace to be harvested and sold together.
How does one tell poor quality fingerlings from good quality fingerlings?
The characteristics of poor quality fingerling include the following: –
Fry of mixed fish types is not good fry.
This often happens when farmers do not get fry from a designated fry producer. Examples: farmer-to-farmer fry supply or from the wild streams, river & lakes.
Fry of mixed age or size groups is not good quality
Size normally indicates age. Therefore, the bigger fry are older than the smaller ones. Fry of mixed sizes are usually found when fry is collected from ponds not intended specifically for fry production (farmer-to-farmer fry supply), or when it is collected from the wild (streams, river & lakes). Fry of mixed sizes or ages result in mixed size harvests as shown in figure 3.2. In most cases the older fish start reproducing in the pond and congest the pond much earlier when majority of the fish are still small. The stunted fish are sold at a reduced price and the farmer loses money.
Fry of uniform size/age is good.
Size indicates age. Therefore, uniform size is also uniform age. In the Catfish (“mmale”) fry, when some individuals are larger than others, the larger fry feed on the smaller ones. When fry of varying sizes is stocked, the overall harvest is low, consisting of few numbers although their sizes may be big.
Stunted is not good
Stunted fish is fish that is too old for its size. It is usually a result of inadequate feeding of fry or feeding with poor quality feed. The fry remains small while the age is advancing.
The easiest way to recognise stunted fry is large heads with bulging eyes contrasted with its small body size.
Any lame (diseased) fry is not good for stocking
There are several types of fish diseases. A diseased fish does not grow well and may die. Fry showing any signs of disease should not be accepted for stocking.
Fry may be lame (with deformities) as a result of:
- serious injuries acquired due to bad handling
- feeds that lack certain nutrients (especially minerals & vitamins)
- a heritable factor (gene)
Lameness usually affect the skeleton and the fish does not grow well. Fry showing any sign of disease is not good for stocking.
Fry that is badly
Injury results when fry is badly or roughly handled. The bruised fry may get infection and die. Or it may take some time for the wounds to cure. During that period, it does not feed and it grows slowly. It is small at harvest.
Fry collected from the wild (stream, river or lakes) is not
Fry of poor genetic quality
Fry may be of poor quality because of factors inherited from generation to generation (genes). External signs of genetic quality may not be obvious to ordinary people. They may not tell in advance that it is poor fry. They only find that the fish does not grow well.
How to identify poor genetic quality of fry is not in the scope of this manual. The only way to avoid these uncertainties is to get the fry from a certified fish breeder.