For information on Animal Welfare and Organic Certification Norms see here

Starting aquaculture as an economic enterprise, like any other economic enterprise, should be taken seriously. One needs to acknowledge that it involves making a significant investment decision and requires serious commitment. This is always true when deciding on the feasibility of any economic investment.

Marketing is normally overlooked by many entrepreneurs and yet aquaculture production, like any other serious investment, should target specific market(s). Indeed for any aquaculture enterprise to be successful, it must target a specified market or markets.

Any serious entrepreneur will produce goods which match the needs and wants of the customers they wish to serve. Therefore, one must make a decision on what to produce based on what the market wants.

Therefore, to avoid uncertainties and eminent failure, the first questions that an investor must ask and get answers to, are:

It is important to consider marketing alternatives to avoid disappointment where a target markets collapse. For the marketing alternatives chosen or considered, product volumes and size preferences, costs associated with the marketing, and relevant legislations should be considered very carefully. Alternative markets for aquaculture products to consider include:

The reason for starting any enterprise is to make profit/gains. This applies to all kinds of enterprises including aquaculture. In aquaculture enterprises, proper management of biological aspects of production is very important, so are the financial aspects of the enterprise. An entrepreneur must beforehand evaluate the viability of the proposed enterprise and continue to monitor its financial health during operation.

One way of evaluating whether an opportunity such as a new aquaculture investment is worthwhile in the long-term, or to chose between aquaculture opportunities which vary in size, is by use of capital budgeting. Popular methods of capital budgeting include net present value (NPV), and internal rate of return (IRR). Pay-back period (PBP) and the breakeven point (BEP) are also used as indicators of feasibility of investments.

Net Present Value (NPV) is used in the analysis of the profitability of an investment or project to give indication of the today's value of what will be earned in future. It is the futures net cash inflows discounted to today's value. If the NPV of a prospective project is positive, the project is profitable but if it is negative, the project should be abandoned because cash flows will also be negative. The higher the NPV value, the more profitable an investment is.

Where:
P = The net cash flow
i = The interest rate or the marginal cost of capital
t = Expected project life
INV = Initial investment

In addition to the formula, net present value can be calculated easily using tables, and much easier by use of computer soft wares like the Microsoft Excel spread sheet.

Internal Rate Of Return (IRR) indicates the estimated rate of return that a project is expected to generate to an investment. This can be viewed as the efficiency of an investment to turn profit.

IRR is the interest rate at which the NPV is zero. It equates the present value of the expected future cash flows or receipts to the initial investment. Equation used for IRR is that for NPV, it is solved for i, the interest rate at which NPV = 0.

IRR can be calculated easily by use of computer softwares like the Microsoft Excel spread sheet.

When evaluating possible investments options, it is important to remember that the NPV method is better that the IRR. The major limitation of IRR measurement is that it uses one single discount rate to evaluate every investment. However, discount rates do change significantly and therefore without modification, IRR evaluation will not be adequate for long-term projects for which discount rates are expected to vary.

Pay Back Period (PBP) is the time required to recover the cost of an investment through the net cash revenues it generates. It is calculated by dividing the initial investments cost by the accumulated profits before depreciations. However, this analysis does not take into consideration cash flow after the payback period. This method should only be used therefore as a first approach at the initial stages of evaluation to give an indication of the payback period and may not be relied upon to rank investments on basis of viability. PBP is given as:

PBP=I/E

where:
PBP = payback period in years
I = initial investment
E = Accumulated profits before depreciation

Breakeven Point (BEP) describes how much a project must produce to cover for the total cost of production. At the BEP, the revenue generated by a project equals the total cost incurred. An investor will need to know this to weigh this against production possibilities available. However, this method like the PBP should only be used as a first approach before proper evaluation is conducted because it does not show profitability of projects.

BEP considers the Economics of Scale which means the quantity of fish needed to be produced and sold at the current market price to pay all cost of the operation and make enough profit for the owner. In general the smaller the system, the more it costs to build and operate per quantity produced. This is because certain fixed costs remain the same no matter how much fish are produced.

For aquaculture investment, BEP can be derived for production quantities and produce prices. BEP analysis for production quantities is derived by calculating how much an enterprise should produce per hectare, considering the estimated market prices for the products, to be able to cover for the total production cost. The BEP for the produce prices is calculated by deriving the price at which the produce must be sold to cover the total cost of production.

BEP for production quantity is given as:

BEP for produce price is given as:

Financial ratios are used to give an indication of not only how likely a project will turn a profit, but also how that profit relates to other important investment characteristics of the project. High revenues alone do not necessarily translate into profits for the investor. A project must have the ability to clear all of its expenses and costs. These ratios are used to assess a business's ability to generate earnings as compared to costs incurred during a specific operation. They provide a comparison of profits generated and what have been invested in a project. For most of these ratios, having a higher value is an indication that the investment is good. Such ratios will include return on investment, return on equity, return on asset and operating profit margin ratio.

These ratios are derived as:

Sensitivity of an investment to aspects of production is very important. Some of these aspects can be very volatile and their changes might have enormous effects on the profitability of projects. For investors to be able to make choices on where and how to invest, they need to know how likely variations on production output, cost of inputs or even changes in the market prices for the products will affect their future cash flows and net incomes.

To be able to carry out a proper sensitivity analysis, an entrepreneur needs the following information for each of the investment type:

It is important to point out that there are experts in aquaculture economics in Kenya who can do these analyses for potential investors. Unless the investors are themselves conversant with the analysis, they need not struggle to do them but consult the experts.

Commercial aquaculture can result in good profits but it can also result in meaningless gains or huge losses. The reasons for failure are diverse but include:

There is no need to start something that you do not know whether it will make intended gains. It is therefore important to find out in general terms, the costs and returns of the proposed aquaculture venture before investment is done. To do this, you need to do a budget of your enterprise to see how it will operate. An enterprise budget provides information on annual cost, annual returns and capital investment requirements for a particular enterprise. Many farmers budget in their heads and end up making wrong decisions. Good budgets should be written so that they can be reviewed as times goes by. Most of the information needed for a good budget is available locally e.g. past experience, farm plan, agricultural input dealers for input costs, aquaculture product dealers for fish prices etc.

This refers to gross returns or total sales from the farm. It is the income generated from the sale of farm produce e.g. fish, fingerlings etc. They are estimated by multiplying the total expected harvest weight (quantity) with the expected price per unit weight (kg).

This is also referred to as operating costs. These are costs that vary with production or expenses related directly to the quantity of fish produced for market.

All production costs/expenses are itemized and they include; Cost of fingerlings, feeds, labour, interest on operating capital etc.

Interest on operating capital is a variable cost and is a charged for a loan required to purchase production inputs

Total Variable costs (TVC) is the sum of all variable costs

These are costs that are incurred regardless of the level of production (operation). They include; depreciation, interest on investment capital and other costs not related to active production of the business e.g. insurance. They are also referred to as ownership costs.

Total fixed costs is the sum of all fixed costs.

Net returns: This is the difference between gross receipts and total costs which is the indication of the amount of profit earned.

Table 1: An enterprise budget for a hypothetical fully operational tilapia /catfish farm

One useful tool for planning the use of money in an aquaculture enterprise is a cash flow budget. A cash flow budget is an estimate of all cash receipts and all cash expenditures during a certain time period. Estimates are made monthly, bimonthly, quarterly or annually. Estimates can include non-farm income and expenditures as well as farm items. Cash flow budgeting looks only at money movement, not at profitability. Non-cash revenue or non-cash expenses, for example depreciation, are not considered.

A cash flow budget is a useful management tool because it:

Items to be included in a cash flow budget include:

Each type of revenue is charged during the specific period when it is occurred.

Cash flows differ depending on the purpose for which the analysis is being developed. You could have:

Also expenses associated with the purchase of capital assets or breeding stock are included.

Note: All expenses are summed to obtain total cash outflow.

The following are the important commercial aquaculture species cultured in Kenya:

The importance of proper designs, construction and the need for involvement of experts during the process of setting up aquaculture production units is paramount. Ideally, production units should be designed in such a way to allow total control of:

The production site is of great importance. It does not only dictate the fish species to be produced but also important, the cost of construction is directly related to the nature and location of the site. A good site should therefore meet the following criteria:

Once the site has been identified, surveyed and the producer has made decision on the number and sizes of ponds that will be needed when the farm is fully operational, it is time to make a decision on the design of the ponds.

Step 1. Mark out the area that the pond will occupy using wooden pegs and strings and then remove all the vegetation.

Step 2. Remove the top soil and keep it in a good location close to the site. It will be used to cover the pond bottom and the dyke tops to enhance fertility. Remember that if the soil is kept far away, this will increase the cost of pond construction since the soil will need to be brought back.

Step 3. Clear the area within the pond limit of all vegetation including the area within 10 m of dykes and pond structures and any access, water supply or drainage area.

Step 4.Establish a Temporary Bench Mark (TBM). A bench mark is a mark on the ground that establishes the elevation of a place and is used as a reference point for all other elevation. This will allow you to determine and check by use of levelling equipment (e.g. spirit level) the elevations of the dykes, canals and other structures. The TBM should be set and permanently fixed in a protected location during the whole construction period.

Step 5. Using spirit level, measuring tape, pegs and strings, mark out:

A site pegged ready for digging and filling

© Mbugua Mwangi, Kenya

• The dykes
• Dyke slopes
• Inner and outer toes
• The pond bottom

Step 6. Using the determined pond depths and the actual elevations of the site, determine which areas need digging and which need filling. This is very important because it eliminates unnecessary movements of soil and thus keeps the construction cost at a minimum.

Note that the more gentle the slope, the more solid the pond, but very gentle slopes make ponds more expensive and make rooted weeds control difficult. A slope of 50% is the minimum recommended

Through experience in Kenya, one pond of 100 m2 will take 15 people about 8 days to complete, working 8 hours a day.

Tilapias are heterogeneous in their feeding. They are hardy, have rapid growth, and have ability to consume and efficiently assimilate a wide variety of foods. Various species are omnivorous; others are phytoplanktonous while others are macrophyte feeders.

In natural water bodies, tilapias mature in about two to three years. Under culture they tend to mature early. Sexual features distinguishing males from females are clear when fish mature (about 15 cm in Tilapia zillii and 10 cm in Oreochromis niloticus). Males have two orifices situated near the ventral (anal) fin, one is the urinogenital aperture and the other is the anus. The females have three orifices, the genital opening the anus and a urinary orifice (but difficult to visualize with the naked eyes). Separation of males and females can be made easier by applying dye (India ink, indigo, etc.) to the papilla with a cotton swab to outline the male and female openings.

Optimal Temperature
Temperature affects fish distribution, survival and growth, rate of development, reproduction and even susceptibility to diseases. Various species and strains of tilapia differ in tolerance to low temperatures, but growth is generally limited at water temperatures below 16°C and most become severely stressed at 13°C. Death occurs from 12°C with few surviving temperatures below 10°C. Most will not feed or grow at water temperatures below 15°C and will not spawn below 20°C. The normal water temperature should be between 20 to 30°C. Metabolic rate rises at higher temperatures which lead to death.

Optimal Dissolved Oxygen (DO)
Tilapias are able to tolerate low levels of ambient oxygen. Usually, well fertilized ponds will have low levels of oxygen early in the morning. Night activities are dominated by respiration and decomposition which reduce DO. Larger fish are less tolerant than juveniles. This could be due to the difference in their metabolic demand. The optimal DO for tilapia culture is 4 mg/litre (50%) and should not go below 2.3 mg\litre.

Salinity
All tilapia are tolerant to brackish water. The Nile tilapia is the least saline tolerant of the commercially important species, but grows well at salinities up to 15 ppt. The Blue tilapia grows well in brackish water up to 20 ppt salinity, and the Mozambique tilapia grows well at salinities near or at full strength seawater

pH
Tilapia can survive in pH ranging from 5 to 10 but do best in a pH range of 6 to 9.

Ammonia
Massive tilapia mortality will occur within a few days when the fish are suddenly exposed to water with unionized ammonia concentrations greater than 2 mg/l Prolonged exposure (several weeks) to un-ionized ammonia concentration greater than 1 mg/l causes deaths, especially among fry and juveniles in water with low DO concentration.

Nitrite Nitrite is toxic to many fish and chloride ions reduce the toxicity. Tilapia are more tolerant to nitrite than many cultured freshwater fish. In general, for freshwater culture the nitrite concentration should be kept below 27 mg/l.

Pond culture is the most popular method of growing tilapia in the world. They are grown in fertilized ponds where the fish utilize natural foods from ponds. Management practices of the systems ranges from extensive; using only organic or inorganic fertilizers, to intensive systems, using high-protein feed, aeration and water exchange. The major problem to overcome in this system is the prolific breeding of the fish that occur in ponds under mixed sex culture. This breeding if not controlled results to overcrowding in the ponds. The end result is stunted growth yielding small size fish (less than 100 g) which may not be of market value. In mixed-sex populations, the biomass of juveniles can make up to 70 percent of the total harvest weight. Therefore strategies for producing tilapia in ponds should aim at controlling spawning and recruitment.

For easy management and economical operation in Kenya, grow out ponds should be about 1 to 2 metres deep and at least 300 sq metres for semi-intensive production of tilapia. A harvesting sump in the pond behind the drainage outlet is needed to concentrate the fish in the final stage of drainage. The pond should be drained completely and be allowed to dry to eradicate any fry or fingerlings that may interfere with the next production cycle. This will also kill some parasites, frogs' egg and other unwanted organisms that may be in the ponds.

Under mixed-sex culture of tilapia, both males and female are cultured together but harvested before or soon after they reach sexual maturity. This minimizes chances of recruitment and overcrowding. The disadvantage in this is that fish are harvested at a smaller size due to the limited growth period. In this culture practice, fish are usually stocked at low rates to reduce competition for food and promote rapid growth. One month-old, 1-gram fry are stocked at 1 to 2 per square meter and grown for about 4 to 5 months. In cold areas where the water temperatures are low and therefore growth is slow, tilapia might not reach marketable sizes in that period.

Newly-hatched fry should be used all the time because older ones will reach sexual maturity at a smaller, unmarketable size. They could also be mature fish but stunted. Supplemental feeds with 25 to 32 percent protein are generally used. The average harvest weight is about 250 g and total production about 0.25 kg/sq m for a stocking rate of 1 fish/m2. Higher stocking densities can be employed to achieve higher production but must be combined with very good management. Expected survival is about 80 percent.

To overcome the problem resulting from prolific breeding of tilapia, ponds are stocked with males only because the males grow almost twice as fast as females. Male fingerlings can be obtained by three methods:

Integrated systems
Manure application can be made easy by placing animal production units adjacent to or over the fish ponds so that fresh manure can easily be delivered to the pond on a continuous basis. This also allows the feed wasted by the animals to fall into the fish pond and utilised by the fish. Effective and safe manure loading rates are maintained by having the correct number of animals per pond surface area.

Chicken/fish farming
Maximum tilapia yields are obtained from the manure output of 5,000 to 5,500 chickens/ha, which deliver 100 to 113 kg (dry weight) of manure/ ha/day. Several crops of chickens can be produced in one fish production cycle.

Duck/fish farming
Ducks are grown on ponds at a density of 750 to 1500/ha. The ducks are raised in confinement, fed intensively, and allowed a small portion of the pond where they forage for natural foods and deposit their manure. Ducks reach marketable size in 10 to 11 weeks and therefore staggering production cycles is needed to stabilize manure output.

Pig house with fish pond

© Stephen Gikonyo, Kenya

Pig/fish farming
Approximately 60 to 70 pigs/ha are required to produce a suitable quantity of manure (90 to 100 pounds of dry matter/acre/day) for tilapia production. The pigs are usually grown from 44 to 220 pounds over a 6-month period. In certain cultures and religion, where pigs are considered unclean, used of pig manure might reduce the marketability of the fish.

Fish produced for consumption should be harvested when they reach market size. In Kenya, tilapia are ready for harvesting within six to nine months depending on the size at stocking, target harvest size, water temperature and level of management employed. The time of harvesting is determined through regular sampling which should be done monthly. A day or two before harvesting, feeding and fertilizer application should be stopped. During harvesting:

Although tilapia breed freely in ponds, it is important for farmers (producers) to consider using properly produced fingerlings. They need to invest in hatcheries for fry and fingerling production. Quality fingerlings in tilapia aquaculture are very important. For this reason it is advisable for farmers to generate their own fingerlings if they can not ascertain the quality of those from other sources. Poor fingerlings result in poor harvests.

Developing a hatchery will allow the farmer to have ready fingerlings whenever he needs them. As long as the demand for fingerlings exists, a well-managed hatchery can turn out to be a good business.

This is the simplest and most common method of tilapia fingerling production in Kenya. A properly constructed and well fertilised pond serves both for breeding and rearing fry. Brooders are stocked into the ponds and allowed to spawn naturally. The brood fish are stocked at the rate of 100 to 200 kg/ha at a sex ratio of 1:3 or 1:4 (males to females). A female brood fish of 90-300 g produces as much as 500 eggs per spawning. They should produce 6 - 15 fry/m2/month. To increase seed production, use larger brooders. Brooders of 1 - 1.5 kg can produce 45 fry/ m2/month. For this case, you need to harvest every 17-19 days.

Harvesting fry from the ponds is done every 15 - 21 days (More frequently where average water temperatures are above 25°C). The brooders can be used for 3 - 5 years. Fry harvesting should be done by hand scoop nets along the edges of the pond to minimise pond disturbance and fry mortality.

Yields of up to 400-3,000 fry/m2/month can be realised using this method.
An advantage of using the tank method is that they are easy to manage. On the other hand, tanks are often relatively expensive to set up compared to ponds and hapas.

Tilapia males are preferred for culture because they grow faster than females. Females use considerable energy in reproduction and do not eat when they are incubating eggs.

Males only culture permits the use of longer culture periods, higher stocking rates and fingerlings of any age. High stocking densities reduce individual growth rates, but yields per unit area are greater. If the growing season can be extended, it should be possible to produce fish of up to 500 grams. Expected survival for all-male culture is 90 percent or greater. A disadvantage of male mono-sex culture is that female juveniles are discarded.

Females included in a population of mostly male tilapia affect the maximum attainable size of the original stock in grow-out. A stocking rate of 2/m2 is commonly used in Kenya to achieve yields of 1kg/m2. At this stocking rate the daily weight gain will range from 1.5 to 2.0 grams. Culture periods of 6 months or more are needed to produce fish that weigh close to 500 grams. There are cases in Kenya where stocking densities of 6 juveniles/m2 is practiced with a production of up to 3kg/m2. Higher stocking densities will require water aeration and sub-optimal feeding rates may have to be used to maintain suitable water quality.

Different fish species have different and specific range of water quality aspects (temperature, pH, oxygen concentration, salinity, hardness, etc.) within which they can survive, grow and reproduce. Within these tolerance limits, each species has its own optimum range, that is, the range within which it performs best. It is therefore very important for fish producers to ensure that the physical and chemical conditions of the water remain, as much as possible, within the optimum range of the fish under culture all the time. Outside these optimum ranges, fish will exhibit poor growth, erratic behaviour, and disease symptoms or parasite infestations. Under extreme cases, or where the poor conditions remain for prolonged periods of time, fish mortality may occur. Pond water contains two major groups of substances:

The composition of pond water changes continuously, depending on climatic and seasonal changes, and on how a pond is used. It is the aim of good management to control the composition to yield the best conditions for the fish. For producers to be able to maintain ideal pond water quality conditions, they must understand the physical and chemical components contributing to good or bad water quality.

Plankton are small often microscopic aquatic plants (phytoplankton) and animals (zooplankton) found suspended in the water column. Phytoplankton form the base of the food chain while zooplankton form the second link in the chain in aquatic systems such as ponds.

Plankton are small often microscopic aquatic plants (phytoplankton) and animals (zooplankton) found suspended in the water. Phytoplankton form the base of the food chain while zooplankton form the second link in the chain in aquatic systems such as ponds. [pIn addition to their role as food for fish in ponds, phytoplankton produce large amounts of oxygen for the pond during the day by photosynthesis providing dissolved oxygen (DO) in ponds. Low phytoplankton density in ponds means less food and DO for the fish. On the other hand, too much (algal bloom) lead to minimised sunlight penetration causing algal deaths. Less phytoplankton and decomposing plankton also lead to less food and DO for the fish. Good water quality, in relation to plankton therefore means water with just right bloom. Visibility in a pond with the right plankton density should be about 30 cm. [/p/]

How to measure turbidity:

• If it is well below your elbow, plankton turbidity is very high
• If it reaches to about your elbow, plankton turbidity is high
• If it reaches well above your elbow, plankton turbidity is low.

• 1 kg of fish waste per kg of fish produced
• up to 70% of the nitrogen load in the system
• build-up of ammonia and nitrite
• reduction of dissolved oxygen

• pH
• Alkalinity
• Hardness
• Dissolved gases: oxygen, carbon dioxide, nitrogen, ammonia
• Salinity
• Essential nutrients: N, P, K

Soil pH and Acidity

How to correct the pH of your pond water
Pond water with pH unfavourable for fish production can be corrected by:

• If the pH is below 6.5 (at sunrise), use lime and alkaline fertilizers
• If the pH is above 8.5 at sunrise, you can use acid fertilizers

How to keep soil pH at the right level

• Drying the pond for at least two weeks after each harvest before refilling and restocking.
• Applying lime (preferably agricultural limestone) to the pond after each harvest. Normally lime should be applied to the pond bottom before it is refilled, but if necessary, it can be applied to the water surface after filling the pond. Only recommended liming materials and application rates should be used.

Pond water pH varies over the course of a 24-hour day. This variation is related to the light intensity which is important in photosynthetic activity of phytoplankton.

• pH is lowest at sunrise and as photosynthesis increases as the light intensity increases, more and more carbon dioxide is removed from the water by the plants causing the pH to increase
• A peak pH value is reached in late afternoon.
• As the light intensity starts decreasing, which reduces photosynthesis less and less carbon dioxide is removed from the water; as respiration adds more carbon dioxide to the water, pH starts to decrease.
• At sunset, photosynthesis stops, but respiration continues for the rest of the night. More and more carbon dioxide is produced, and pH keeps decreasing until sunrise, when it reaches its minimum.

Dissolved oxygen in fish ponds
The most important gas dissolved in water is oxygen. Dissolved oxygen (DO) is essential for respiration and decomposition.
Dissolved oxygen in water comes from atmospheric oxygen and photosynthesis. The atmospheric oxygen diffuses and dissolves into the water. But the diffusion and its subsequent dissolves into water is a slow process. The major source of dissolved oxygen in ponds is photosynthesis. However this process depends on the amount of light available to the aquatic plants in water (Phytoplanktons). Therefore:

• Oxygen production decreases during cloudy days
• It stops at night
• It decreases in increase in water depth the rate of the decrease depending on the water turbidity

How to measure Dissolved Oxygen (DO)
DO can be measured by chemical or by electrical methods. Chemical methods rely on the use of kits which can be bought from shops dealing with laboratory equipment. They contain chemicals and equipment necessary to determine the DO content with sufficient accuracy for pond management purposes.

Electrical methods use an oxygen meter, this too can be bought from laboratory equipment shops but it is expensive. Using this equipment, DO can be measured directly from the pond at any depth. DO and water temperature should be measured at the same time so as to be able to relate the DO to the temperature. DO is expressed as mg of oxygen/litre of water (mg/l).

There may be very little oxygen left by morning and fish may suffocate if corrective measures are not taken. In over fertilised ponds, where there is very high plankton density and high turbidity, the DO content of the bottom water may become anoxic (without oxygen) even during the day. The fish will concentrate at the surface of the pond to survive. This will be much worse at night.

Proper pond management can also improve the DO content of the water. The following measures can be taken before any emergency happens:

It is desirable to maintain both alkalinity and hardness at 40 - 70 mg Calcium carbonate per litre. This can be done by:

Un-ionized ammonia (NH3) concentrations in pond water should be kept below 0.5 mg/l Concentrations of this form of ammonia, which is toxic to fish, are influenced by DO, pH, and alkalinity, therefore it is important to manage this by:

Compared to terrestrial animals, fish have certain specific characteristics in terms of dietary requirements:

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.

3. Complete feeds are made from a mixture of carefully selected ingredients to provide all the nutrients necessary for the fish to grow. They are made in a form which the fish find easy to eat and digest. These feeds are difficult to make on the farm and are usually expensive to buy. 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.

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.

The purpose of feed formulation is to ensure that the aquaculture diets meet the nutritional needs of the fish under culture during it various stages of growth. Therefore, for one to be able to formulate a specific feed for a particular fish, they need to know the following nutritional needs as regards the fish:

Occurrence of disease and parasites in farmed fish is mainly as a result of poor husbandry. Disease causing organisms are always in the environment fish live in and they cause few problems. The pathogens naturally exist in an unstable "equilibrium" with their hosts until this balance is disturbed through environmental changes and human activities. Fish are stressed through inadequate dietary or environmental conditions. The water quality parameters such as pH, temperature, dissolved oxygen may lead to outbreak of disease pathogens and parasites. Pathogens naturally exist in an unstable "equilibrium" with fish.

It is better to try to prevent diseases than to wait to cure them once they start to cause problems. To cure a fish disease is much more difficult and may require the services of a specialist. By the time proper treatment can be sought, the disease may have caused a lot of damage. Most disease problems in aquaculture result from things that can be avoided. Some fish stressors that lead to diseases that need to be avoided are:

Disease, parasites or pathogens may enter fish through gills, penetration of egg membrane, ingestion and rupture of skin, wounds or through the digestive tract. Fish diseases may cause severe losses in fish farms through:

Disease, parasites or pathogens may enter fish through gills, penetration of egg membrane, ingestion and rupture of skin, wounds or through the digestive tract. Fish diseases may cause severe losses in fish farms through:

(i) Bacterial - which causes diseases like fin rot and tail rot

(ii) Fungal infections - wooly or cottony patches on the surface of fish, and gill rot causing asphyxia.

(iii) Parasititic

• Ectoparasites - causing Black spot, white spot, fish louse and nematode.
• Endoparasites - like the Contraceacum, and the Ligula intestinalis.

(iv) Dietary - High carbohydrate levels in trout feeds, lack of proteins and lipids will result to liver tumour.