IMPORTANT DETAILS IN SETTING UP A FISH FARM

 

Why fish farming?                  

The startup investment is low and you can start with any capital. The mortality rate is very low when compared to other agro enterprise. You can even develop your own feed and start feeding them with if after 2 -3 months .You can raise your fish to any size you want and start making profits. Returns are very attractive and cost of maintenance is very low. You can decide to diversify your business like packaging fresh and smoked cat fish, opening a fish pepper soup joint to triple your profits or start fish seed production to fish farmers.

CONSTRUCTION OF POND

Earthen pond: This involves digging the soil usually clay (25 %clay) to a depth ranging from 0.5- 1.0 m at shallow end and 1.5- 2.0 m at the drain end to raise fish. Pond can be of any shape as long as it is well constructed. However rectangular or square shapes are considered the best. This is usually practicable in swamping environment .This rule away the problem of water maintenance as there is natural flow in and out of water in the pond

Concrete pond: Here, 4-5 coaches of blocks are used to construct the pond above the ground level, using cement, sand and gravel in ratio 1:2:4 respectively with water .The pond floor should be well concreted to a thickness between 7.5cm- 10cm. Wall should be plastered to a thickness of 5cm. Water tap should be well connected to allow free flow in and out of water. This particular type has the advantage of you monitoring the hygiene of your fishes.

 

PREPARING POND

Preparation of old and new pond is done to create a requisite environment for the well-being and growth of fish to be stocked. The principle of preparation is basically the same for old and new ponds, though some pond like earthen and concrete may require you applying lime to kill all possible bacteria that can affect fish. This process is followed by fertilization by applying organic manure like dried chicken waste tied in a sack bag or cow dung or inorganic manure NPK, SSP, TSP, depending on the type of pond. This is followed by stocking with healthy fingerlings from reliable farm and continuous feeding. It is advisable as a beginner to start with juvenile fishes, which you can get at N25/ juvenile. It is recommended that fish should be fed regularly, at least twice daily at specific times usually 10 .00am and 5.00 pm at special feeding spot and by gradual broadcast till the fishes ceases to come up and feed. Overfeeding should be avoided to prevent fouling and pollution of water by unconsumed feed decomposed to form smelly and harmful gases like ammonia, hydrogen, sulphide and carbon dioxide which have adverse effect on fish growth and survival. Water should be changed regularly when due.

 

Drainage

Select site and construct ponds so they can be drained by gravity flow. The lowest part of the pond must be higher than the canal or ditch into which the pond is being drained. Pond bottom should be flat and slope from the shallow to the deep end. Slope of bottom should be about 0.1 - 0.2 feet per 100 feet from shallow to deep end. A flat sloping bottom is necessary for harvesting and draining. Do not build a harvest basin inside or outside the pond.

Inside drain: Most common is the turn-down pipe or modified Canfield outlet which is located at the lowest point in the pond. The level of water is determined by pivoting the pipe up or down. It must be securely held in position to prevent unplanned drainage. This can be done with a chain from the end of the drain to a post on the bank. Heavily grease swivel joints to allow easy movement. Maintenance of swivel joints can be a problem since work has to be done under water or when the pond is drained.

Outside drain: The drain pipe is laid through the levee at the lowest point in the pond. The inside end of pipe is screened and extends out from toe of slope at least 5-10 feet to prevent clogging caused by sloughing of dirt from levee. The outside end of the pipe should extend at least 5 feet past the toe of the slope to prevent excessive erosion of the levee when water is being drained. The end of the pipe is fitted with a "T" and a stand pipe of a height that

 

Time

Initial stocking is done as soon as there is water in the pond, and catfish of an acceptable size are available. When a pond is "clean cropped," or all the fish are harvested at one time, restock the pond as soon as it is one-fourth to one-half full and stocker-sized catfish are available. When a pond is "topped," or multiple harvested, restock as soon as possible after harvest with one 5-8 inch fingerling for each fish harvested. In a topping or multiple harvest production system, a pond is stocked initially and fed until about 1/4 to 1/3 of the fish are larger than 3/4 pound. At that time, seine the pond with a seine having a mesh size of 1 3/8 to 1 5/8 inches. The seine will capture those fish that weigh 3/4 pounds or more and will allow smaller fish to escape. Replace fish removed by stocking one fingerling for each fish harvested.

 

Feeding - Remember "no feed, no gain!" Feed size. It is important to match feed size to fish size. Feed must be small enough so fish can eat it. In ponds with mixed sizes of fish, use mixed feed sizes or use feed that can be eaten by the smaller fish. Quality of feed. Use feed that has 32-35% protein. Vitamins, particularly Vitamin C, must be added. Use floating feed when water temperatures are above 60ºF (15.6ºC) and sinking feed when temperatures are lower

Feeding rates - Several factors control the amount of food fish eat:

(a) Water temperature

(b) Water quality (oxygen, pH, etc.)

(c) Size of the food

(d) Palatability or taste of the food

(e) Frequency of feeding

(f) The way the fish are fed

(g) Location of feeding sites

(h) Type of pellet used, floating or sinkin

 

Feeding time and frequency

Feeding twice daily, if possible, will usually improve food consumption and food conversion. This means that one-half of the daily allowance is fed in the morning, and the other half in the late morning or early afternoon.

Research indicates that feeding in the late afternoon increases the amount of fat deposited, and this can affect the quality of the processed fish. Since low oxygen concentrations are usually at their lowest in the morning, it is generally best to wait until 8 or 9 a.m. before feeding.

Also, it is best not to feed late in the afternoon to prevent the fishes' increased oxygen requirement from coinciding with decreasing oxygen concentrations in the pond. Feeding daily can reduce production time by four weeks when compared to feeding only six times a week.

Feed along the entire length of the pond and preferably along two sides. By feeding along two sides, more fish have a chance to get their share, thus resulting in better growth rates and feed conversions.

Remember that feeding is the most important task in the production of catfish; thus the person responsible for feeding should be an experienced fish culturist. Under normal circumstances, the only time fish in the pond are seen is when they are coming up to feed, and their feeding behavior can be an important clue to the general health of the fish and the condition of the pond. Therefore, the person feeding must be able to tell whether or not the fish are feeding normally. If the fish are not feeding normally, the feeder must recognize the fact and alert the manager that a potential problem may be developing.

Holding fish without feed for a minimum of 48 hours in good quality water at the hatchery or nursery prior to their collection and transportation to the grow-out farm. The major objective of doing so it to allow the fish empty their guts in order to reduce stress to the fish and maintain water quality during transit.

 

Record keeping

You must know the number of fish and the weight of fish in every pond at any given time if you want to be successful at raising fish. If the weight of fish in a pond is underestimated, not enough food will be fed, resulting in poor growth, poor feed conversions, and increased time required to get the fish to harvestable size. If the weight of fish in a pond is overestimated, the result will be overfeeding, poor feed conversions, and very likely, severe water quality problems.

An important reason for keeping good records is that many lending institutions require good records before they will lend money. Also, without good records you don't know if you are making or losing money, and you can't identify problem areas that need correcting for the most efficient and economical management.

Daily Feeding Record

Record the amount fed daily to each pond on this form. At the end of the week total the amount fed for the week.

Daily Pond Record

 

Pond #	Sun.	Mon.	Tues.	Wed.	Thurs.	Fri.	Sat.	Total

 

Weekly Pond Record

Record date of stocking, stocking rates and weights, amount of food fed weekly, weekly weight gain, and weight of fish harvested for each pond. Other information concerning disease treatments, weed control, etc., can be noted in there marks section. Most of the information required on this form is self-explanatory. The estimated conversion ratio should be determined by you from experience gained from previous years. The estimated conversion ratio can be obtained from Pond Conversion Ratio Calculations, which should be completed as soon as the pond is harvested.

 

Water duality

Maintaining good water quality in production ponds is absolutely essential. Failure to do so will result, at best, in poor growth and high feed conversions or, at worst, a total loss of all fish in the pond. Remember that the fish in the pond are living in their own wastes. Thus, the weight of fish that can be produced in a pond is limited by the ability of that pond to provide adequate oxygen, not only to keep the fish alive but to enable them to metabolize their food and grow, and to break down nitrogenous wastes.

To achieve production rates in excess of 2,500 pounds per acre per year, the farmer must be able to insure that good water quality is maintained 24 hours a day, 365 days a year. Water is the universal solvent; is essential for all life; does not exist in pure state under natural conditions; and is relatively stable both chemically and physically. A fish farmer should be aware of the physical and chemical properties of water:

 

Physical Properties

Water is most dense at 39.5ºF (4ºC). Water colder or warmer than 39.5ºF (4ºC) is lighter. If it were not for this fact, water would freeze from the bottom up, thus no aquatic life could exist in temperate and arctic areas.

Water changes temperature more slowly than the surrounding air or soil changes temperature.

In still water, differences in temperature cause a layering effect known as stratification. Upper layers are warm and bottom layers are cool in summer. The reverse is true in the winter.

Considerable force is required to break down stratification if temperature differences are great.

• Oxygen

Oxygen is necessary for all life to make available energy contained in food. The atmosphere is 21-23 percent oxygen at sea level.

General Biology of African Catfish

In nature, the African Catfish (Clarias gariepinus) tend to live in calm waters with vegetation. Living conditions in such an environment can be harsh. There is often a lot of organic matter in the water. In addition, in several of these locations (for example, in flood plains) the water levels fluctuate seasonally, going up during the rains and receding during the dry seasons. In several of the clarias catfish natural habitats, the water levels drop to the point whereby the water-way almost dries up. The relatively large amounts of organic matter in water coupled with the relatively slow water flows through such habitats result in low levels of dissolved oxygen in the water for prolonged periods and increased acidity of the water. In order to overcome these environmental challenges, the fish have adapted in the following ways:

Low Oxygen Levels – Catfish have developed in addition to gills, an accessory cauliflower like organ (the arborescent organ) that enables the fish obtain oxygen from air when the oxygen levels are too low in water or the swamps have dried out. However, this organ is largely functional in adults. More than 90% of juvenile catfish oxygen consumption is from dissolved oxygen in water whereas in adults, 40% to 50% of the oxygen uptake is atmospheric (Hecht et al., 1997).

2. Body Shape and Features - The fish have no scales, but a relatively thin skin and protective layer of mucus over the skin. Their long cylindrical shape also allows them to easily burrow into the mud when water levels drop to keep themselves moist and cool.

They can only survive in burrowing if there is an air-water interface. In addition, it has barbels that enable it sense its food even though visibility is poor in the swamp. Its flattened mouth is designed so that it can ingest food off the bottom.

3. Feeding Habits - The fish is also an omnivore, meaning it can literally eat almost anything although in the wild adults preferably eat other fish, insects or other forms of aquatic animals. Adult have a diel (twenty four hour cycle) feeding pattern, meaning that they need to hunt once a day, subject to food availability.

Consequently they have a relatively large stomach capable of holding quite a bit of food, unlike the Nile tilapia whose stomach is relative small because it is naturally a browser and feeds several times a day.

4. Social Behaviour – Catfish are extremely social. They tend to live, hunt in tight groups. Hunting as a pack is among their natural feeding strategies (Hecht et al., 1997). They tend to dwell at the bottom.

5. The fish are able to withstand slightly acidic water.

6. The catfish also grows fast and does not become sexually mature until it is about a year old (about 600g) depending on feeding.

Females become mature earlier than males.

The above mentioned attributes, make the catfish a good candidate for aquaculture. However, these biological characteristics affect the fish’s production requirements and potential in the following manner:

1. Low Dissolved Oxygen Levels – Where the water has adequate levels of dissolved oxygen, catfish obtain their oxygen from the water through their gills. Aerial respiration in catfish is largely a compensatory mechanism for the periods when the dissolved levels of oxygen in the pond are low (Lévêque, 1997). However, in order to survive the periods of low dissolved oxygen, the fish must have access to the air otherwise they will die. In addition, the fish spend more energy obtaining oxygen from the air than they would do, when they can obtain it from the water.

In fish farming, the initial limiting factor to production as far as water quality is concerned is oxygen. Because adult catfish have the ability to overcome this by breathing air, higher carrying capacities and feed input level can be accommodated in catfish grow-out ponds as long as the build up of metabolic wastes (ammonia) in the water are kept under control and the fish can access the water surface.

However, because more energy is spent when the fish obtain air from the atmosphere, Feed Conversion Ratios (FCRs) tend to increase, which in turn affects the profitability of the enterprise. Therefore, just because clarias catfish have the ability to withstand situations of low dissolved oxygen, for profitable production, the water quality parameters should as much as possible be maintained within the recommended ranges (see section 5.1. for more details). A minimum amount of oxygen within the water is required for the breakdown of metabolic wastes. Having more oxygen dissolved in water improves the efficiency with which the gills function which is more energy efficient for the fish and results in better growth rates.

2. Body Shape and Features - Because the catfish have no scales, the thin layer of mucus is the only first line of defense against infections whose port of entry into the fish is the skin.

Consequently, removal of this layer of mucus through poor handling predisposes the fish to infection and illness. Catfish, should therefore, be handled with care during routine production operations.

Because catfish are bottom dwellers, most of the time within the pond they will be at the bottom unless there is a reason for them to come up, for example, to feed or gulp air to obtain oxygen.

Consequently, they tend to stir up the pond bottom which makes the water in catfish grow-out ponds muddy (i.e. turbid). Coupled with their burrowing behavior, they also dig into the sides of the pond, creating what is termed as the ‘catfish highway’. This results in breakdown of pond levees, especially when they are not constructed as recommended and in addition increase levels of pond turbidity

Their body shape and the catfish highway they create in the pond enables them to easily escape seining when nets and techniques are poor. They are able to pass under and around the nets. When there is a hole at the bottom of the seine net, and one catfish finds it, because they move in hordes like sheep unlike tilapia, all the others shall be informed and they will all escape in a stream through the hole. Therefore, seine net specifications and seining technique are important; otherwise one can easily come out with an empty net.

3. Feeding Habits – The clarias catfish is omnivorous. This means it can consume a wide selection of food items that allows for a range of options in culture to provide for its nutritional needs. Because of their social hunting behaviour, it is preferable to feed them in ponds from a single place as doing so induces a feeding frenzy that results in the complete consumption of the feed, improved FCRs and reduced feed wastage. This is an important fact as above 60% of production costs are the feed cost (Hecht et al., 1997).

4. Social Behaviour – Pack hunting is a natural feeding strategy in Clarias catfish. Keeping the fish at high densities, consequently results in reduced stress and aggression while stocking at low densities results in the establishment of territories and aggression.

Stocking densities in the pond should be such that:

(i) They are high enough to the point whereby territories are not established, aggressive behaviour is reduced, feeding response is high and feed consumption time is reduced.

(ii) Management requirements to sustain the biomass in the pond do not reach the pond’s carrying capacity limits for the specified management level (see sections 5.3. and 6.2.6. for more details).

5. Most healthy fish tend to swim against a current. Therefore, they will tend to aggregate and swim out of the inlet if water is flowing into the pond during the production cycle. Thus, most escapes of catfish from ponds actually occur through the inlet (Plate 3.3).

Inlets should therefore be set above the water level and well screened (see section 3.1.4. for more details).

 

 

Source of oxygen in water - Oxygen dissolves in water and occurs as a simple solution. It does not combine chemically with water. The rate at which oxygen diffuses into water is governed by physical laws which relate to the solubility of gases. Rate of diffusion can be increased by agitation which allows more contact of surface water with air. Photosynthesis - the single most important source of oxygen in pond water. All green plants manufacture food by a process called photosynthesis. A waste product of this process is oxygen which is given off and is dissolved in the water.

Oxygen cycle - The oxygen concentration in water changes from minute to minute depending on many factors but essentially it follows a definite pattern during any 24-hour period.

The figure below illustrates a typical 24-hour oxygen cycle in a pond.

•  Concentration is lowest at sun-up.

•  Concentration is highest in mid-afternoon.

•  Concentration at dark must be high enough to meet Biological Oxygen Demand (BOD) during the night and with enough left to keep fish healthy.

 

Amount of oxygen water can hold depends on these factors:

Pressure (Altitude) - The amount of oxygen that can be present in water decreases as altitude above sea level increases.

Salinity - of no importance in fresh water.

Temperature - of critical importance in determining the amount of oxygen that can be present in water. As temperature increases, the amount of oxygen that can stay in solution decreases.

Causes of oxygen depletions

Respiration - Uptake of oxygen by plants and animals in the water exceeds the ability of photosynthesis and diffusion from air to maintain oxygen levels adequate for life.

Algae die-off - Color of water will usually change from greenish to a blackish, brownish or clear color. This can be caused by chemical treatments; excessive algae blooms which can release material toxic to itself or other types of algae; and heavy rain or high winds which can force algae to bottom where there may be oxygen deficient water causing a die-off.

Turn-over - As algae blooms become denser in the spring and early summer, light penetration and warming are restricted to the upper layers of water. On bright, still, hot days the surface water warms rapidly, resulting in marked differences in water temperature from top to bottom. The surface water is warm and less dense than the cool water at the bottom, and these layers tend to resist mixing. When this happens, the pond is said to be stratified.

Since there is no mixing of the two layers of water, the bottom layer (hypolimnion) becomes devoid of oxygen by respiration and can develop a high biological oxygen demand. Anything that causes a mixing (turn-over) of these two layers, such as high winds, cold rain, seining, aerators, etc., can result in an oxygen depletion.

Chemical reactions are constantly going on in pond water and mud, and many of these reactions require oxygen. When well water that is devoid of oxygen but rich in iron is pumped into a pond, the iron is changed chemically and forms a reddish-brown precipitate. In this reaction, oxygen is removed from the water. When formalin is added to a pond as a disease treatment, it chemically removes 1 ppm oxygen for each 5 ppm formalin added.

Temperature of water - As temperature increases, the amount of oxygen that can be dissolved in water decreases.

 

Preventing oxygen depletion

 Well water usually has no oxygen and must be sprayed to aerate when being added to pond.

PH

PH is a numerical expression of the acidity or alkalinity of a substance or the relationship between hydrogen (H+) and hydroxyl (OH-) ions

pH values for a given body of water reflect complex interactions between various types of plants, amount of photosynthesis taking place, basic chemical composition of the water supply, and respiration of the living organisms present. pH 4 and pH 11 are the acid and alkaline death points of fish. Optimum pH range for fish culture is about 6.5 to 9.0.

 

Ammonia

Ammonia is present in water in two forms, ionized and un-ionized. The Total Ammonia Nitrogen (TAN) concentration in pond water is the sum of the ionized plus un-ionized ammonia present (NH4 + NH3 = TAN). Nitrogen (N), a major component of protein, is necessary for all life forms. Ammonia gets into a pond in several ways, but the main source is feed. Effective removal of ammonia from the pond depends primarily on biological processes.

Ionized ammonia (NH+) is non-toxic to fish. Un-ionized ammonia (NH3) is toxic to fish.

There are several sources of ammonia in water: metabolic wastes from animals and plants. The major source of ammonia in pond water is fish feed. For each 100 pounds of catfish feed fed, about 2.2 pounds of ammonia is being added to the pond.

• uneaten feed.

• decaying plants and animals.

•  inflowing water.

 

Correct ammonia problems in these ways:

• Lower pH - (usually not economically feasible).

• Stop feeding.

• Flush pond - This does not remove the ammonia but does provide a safe haven for fish until the problem is corrected.

Insure adequate oxygen.

Add 40 pounds of 20% superphosphate (0-20-0) or 20 pounds of triple super phosphate (0-46 -0) per surface acre. Since phosphorus is the limiting factor in the use of ammonia by plants, the addition of phosphorus will stimulate algae growth, thus removing the ammonia in the water to zero in 2 to 3 days. Remember, however, that the increased algae bloom can lead to oxygen problems and the pond must be watched closely

Check ammonia concentrations every 7 to 10 days year-round.

Physical Characteristics

The fingerlings should be of a uniform color and size. Catfish fingerlings usually are darker (blackish) on the top and lighter (creamy) around the belly (see Plate 4.1a). Do not purchase the fish if:

(i) several of them have patches over their body,

(ii) they have less than two barbels, no tail or missing fins,

(iii) they show signs of physical injury or bleeding,

(iv) they are deformed (see Plate 4.1b),

(v) they are less than 10cm in total length.

These are signs of poor condition. Such fish are likely to be already diseased and are less likely to survive transportation or stocking. It is important to stock fish of uniform size otherwise the larger fish will cannibalize the smaller ones. They will also dominate the feeding area which will result in them growing bigger and the smaller fish remaining small. In such a situation, at harvest, there will be only a few extremely

 Physiological Characteristics

The fingerlings in the holding unit in the hatchery should be swimming normally and should be active. Fish remaining up-right, that are sluggish and do not respond to stimuli or prefer to be isolated from the rest of the group, are unlikely to be well

 

Stock Stress-Free Animals

The fish should be stress free, lively and active. Stressed fish start dying about three days after stocking and mortalities can continue for up to a week. It should be noted that, not all the dead fish float to the surface. As has been mentioned above, stress associated with stocking is among the major causes of low survival. However, because the deaths do not occur immediately and dead fish are often picked up by birds at dawn or dusk, many farmers fail to link the ensuing mortalities and low survival with poor handling at stocking. Minimising stress associated with stocking starts at the hatchery. Therefore, take note of the following when you intend to stock your ponds.

4.2.1. Place the Order for Fingerlings from the Hatchery in

Advance

Order the fingerlings at least four days in advance. Re-confirm your collection time for picking up the fingerlings a day or two before the receiving day. This is to give ample time to the hatchery operators to sort, grade and condition the fish a few days before they are transported to the grow-out farm. To enable the hatchery operators sort and grade the right fish and pack it for transportation appropriately the following information must be given when placing your order.

1. The number and sizes of ponds you intend to stock.

2. How many fish are to be stocked into each of the ponds?

3. Size of fish you require. The minimum recommended size for stocking catfish grow-out ponds is 10 cm or 5g. Stocking larger fingerlings (from 10 g up) though is preferable.

4. The destination (location of farm) i.e. how far to travel.

5. On which day and at what time you intend to collect the fish.

6. How you propose to transport it. For example, if you are to use public transport, either you or the hatchery operator might need to arrange for packing boxes so that the transport bags remain secure in the bus.

4.2.2. Handling at the Hatchery.

A hatchery that follows BMPs, should be in a position to undertake the following, to ensure that the fish collected are not stressed, and that they are in the best condition for stocking.

1. Fish should be Conditioned for 48 Hours before Collection. To prepare the order, the fingerlings have to be seined, sorted, graded, counted and then held in holding facilities (either tanks or hapas) with good water quality and aeration as needed, for at least two days prior to collection. The fingerlings are to be left in these holding units without feed until the collection day, but for not more than 3 days. This process is termed ‘conditioning’ the fish. Conditioning provides time for the fish to empty their guts before transportation and for the weak/deformed fish to be identified and removed. Do not transport fish with full guts because they will defecate and vomit in the transportation container, which reduces the water quality by increasing the levels of ammonia and organic load. When their guts are full, the fish require extra levels of oxygen to enable them breakdown the food in their guts. This results in a more rapid depletion of dissolved oxygen levels within the transport container. Holding fish prior to transportation in conditions of poor water quality is extremely stressful, and is a major predisposing factor for disease and mortality. Do not transport fish for stocking that have not been conditioned for at least 48 hours in good holding conditions.