Fishpond Construction and Preparation: Practical Guide

Fishpond construction refers to the process of building and preparing a pond specifically for keeping live fish in a controlled environment or fish enclosures.

How to start a profitable fish farming business in Nigeria

Requirements for fishpond construction

Constructing and preparing a fishpond requires careful planning and attention to detail. The location, size, shape, and depth of the pond will impact which types of plants and fish can thrive. Here are the steps to guide you through the process:

Site selection surveys and setting out.

We’ll cover how to select the ideal pond site and orientation. Here are some key points about site selection for fishpond construction:

·            Purpose (fish culture, water storage).

·            Water (quality, quantity, seasonality).

·            Location. (Dams, basis etc.).

·            Dam fills materials (late rite, rock fill pieces, concrete).

·            Accessibility (for vehicles, equipment etc.)

·            Basin (appropriate for impoundment).

·            Meteorological data (Annual rainfall, temperature etc.)

Excavation

Once these requirements have been carefully verified and deemed suitable, thorough technical surveys are carried out without delay. For the earthen pond (dug out) the procedure is as follows:

For warm water grow out ponds, depth should support temperature stability, water quality management and complete drainage. FAO guidance for African catfish on growing uses an average water depth of about 1 m, while practical earthen ponds are commonly sloped from roughly 0.75 m at the shallow end to about 1 to 1.2 m at the deep end. Design the pond so water drains toward the outlet rather than using one fixed depth for every site. See FAO guidance on warm water fish culture.

A fishpond (concrete) can be constructed as follows

Concrete tanks should be set out on competent ground and built to safely resist soil movement and water pressure. Slab thickness, reinforcement, block thickness and concrete or mortar mix should be specified for the tank dimensions and site conditions; there is no single 100 to 150 mm slab or fixed mix ratio that is safe for every tank. Provide a drainable floor, correctly sized inlet and outlet pipework, waterproof internal surfaces and adequate curing. For larger tanks or uncertain ground, use a competent builder or civil engineer with fish tank experience.

Fishpond Preparation

Do not use one fixed four week waiting period for every new pond. Concrete curing and neutralisation are different from earthen pond fertilisation. Before stocking a concrete tank, allow the structure to cure fully, flush or soak it as needed, and confirm that the water pH is stable. Earthen ponds should be prepared according to soil condition, water quality and the production system.

This period called setting time affords the adjustment of the setting of the component of the newly constructed fishpond.

The concrete portions of the fish tank also undergo a crack free curing process, resulting in a solid and durable structure. Any fault can be rectified too.

The period setting time affords the adjustment or set of components of the newly constructed fishpond/tank and neutralization.

The dug out embankment becomes compacted for stability. The pond basis becomes more mature and acclimatized preparatory to fishpond culture.

Medium Preparation

Water is the medium in which the fish lives. The fishpond medium appropriate for fish culture is P” 7.0 to 8.5. The first process is neutralization. It’s a process of lowering the acidity of the pond medium.

The lime requirement depends on soil pH, water alkalinity and the liming material used. FAO guidance for newly constructed African catfish ponds gives a broad historical range of about 200 to 1,500 kg/ha of agricultural limestone, but the correct dose should be based on actual pond conditions. Agricultural limestone is generally safer for routine pH correction than quicklime. Do not copy a blanket lime dose without testing. See FAO pond liming guidance.

Fish Pond Fertilization

Fertilisation is useful mainly when the production system depends on natural pond food such as plankton. It is not a compulsory step for every catfish grow out pond, especially where fish receive a complete formulated feed.

Do not use one fixed NPK, manure, plant slurry or soybean filtrate rate for every pond. Fertiliser requirement depends on pond fertility, water transparency, dissolved oxygen, pH, fish stage and the type of culture system. Excess organic matter can drive oxygen down and increase ammonia.

For context, FAO African catfish nursery work has used chicken manure at 50 kg per 100 m² one week before stocking to build zooplankton for larvae. That is a nursery pond protocol, not a universal grow out prescription. See FAO guidance on African catfish fry nursing.

Not sure how many fish your pond can carry? See our tilapia stocking density guide for pond, tank and cage rates.

FISH FINGERLINGS.

Fish fingerlings are the basic young fish needed for starting the growing or culture of fish to the table size. They are produced in the hatchery by induced breeding or mating of matured breeders together in hapas, ponds or tanks.

The fries so produced are stocked in ponds or tanks for further nursing to fingerlings which are stocked later for table: size culture.

During this critical period, manage feed and water quality together. Ammonia control depends on avoiding overfeeding, maintaining adequate dissolved oxygen, removing accumulated wastes where the system allows, and using water exchange or aeration when water quality measurements show they are needed. Routine water changes alone are not a substitute for monitoring.

Stocking density must be matched to species, fish size, target harvest size, feed input, aeration and water exchange. The old table on this page mixed units and species and should not be used for farm planning. For African catfish grow out in static earthen ponds, FAO guidance describes roughly 2 to 10 fingerlings per m² depending on target market size and management intensity; higher densities require stronger water quality control. See FAO guidance on African catfish monoculture.

FISH FEED.

Feed is usually the largest recurring cost in intensive aquaculture, but its share of total production cost varies widely with system, feed price, survival, labour, energy and stocking density. Use actual farm records rather than assuming a fixed 75% cost.

COMPOUNDED FISH FEED

Protein requirement depends on species, fish size and feed energy. For African catfish, FAO sources report about 35 to 42% crude protein for some intensive grow out diets, while very small fish may require different feeding programmes. Choose a complete feed formulated for the actual life stage rather than applying 38 to 42% CP to every fish. See FAO African catfish feeding guidance.

Aquatic plants and farm by products may have a supplementary role for species that can use them, but they should not replace a nutritionally complete catfish ration without a tested formulation. The previous fixed slurry and plant filtrate application rates on this page were removed because they were not tied to a defined species, biomass, nutrient analysis or water quality target.

Fish Farm Management

It is crucial to consider the feed consumed by fish in aquaculture. Proper nutrition is crucial for the health, growth, and overall well being of the fish.

Here are some key points to consider regarding fish feed in aquaculture:

1. Balanced Nutrition: Provide fish with a balanced diet that meets their specific nutritional requirements. A well formulated feed should contain essential nutrients such as proteins, carbohydrates, fats, vitamins, and minerals in the right proportions.
2. Feed Formulation: Depending on the species and life stage of the fish, feed should be formulated to cater to their dietary needs. Juvenile fish may require higher protein content, while adult fish may need more energy rich feeds.
3. Feed Ingredients: Choose high quality feed ingredients from reputable sources. Common ingredients include fish meal, soybean meal, wheat, corn, and various micronutrient supplements.
4. Pelleted Feeds: Many aquaculture operations use pelleted feeds as they are convenient to handle, reduce waste, and allow for precise feeding management.
5. Feeding Frequency: Determine the appropriate feeding frequency based on the fish species and their growth rate. Some fish may require multiple feedings per day, while others can be fed less frequently.
6. Set feeding rate by fish size and water temperature. A single 3 to 5% rate is not suitable for every stage. FAO African catfish tables show that the percentage of biomass fed per day generally falls as fish grow; for example, at about 27 to 29°C it can be around 5 to 8% for very small fish, around 3 to 4% near 25 to 50 g, and about 2.5 to 3% around 100 to 200 g. Recalculate biomass from sample weights and reduce feed when appetite or water quality deteriorates. See FAO feeding rate tables for Clarias gariepinus.
7. Feed Conversion Ratio (FCR): Monitor the FCR, which is the amount of feed needed to produce a unit of fish weight gain. Lower FCR values indicate better feed efficiency.
8. Avoid Overfeeding: Overfeeding can lead to water pollution, nutrient imbalances, and wasted feed. It can also contribute to the growth of harmful bacteria and algae in the pond.
9. Environmental Impact: Consider the environmental impact of fish feed production. Sustainable feed ingredients and practices can reduce the overall environmental footprint of aquaculture operations.
10. Feed Storage: Properly store fish feed in a dry and cool place to maintain its quality and prevent contamination.
11. Gradual feeding transition is important when changing fish diets or transitioning between life stages. It helps prevent stress and digestive issues in fish.
12. Research and Adaptation: Stay updated on the latest research and advancements in aquaculture nutrition. Adapt your feeding practices based on scientific knowledge and best practices.

Regularly monitor the health and growth of the fish, and adjust the feeding regimen as needed to ensure optimal growth and productivity.

Working with nutritionists or aquaculture experts can provide valuable insights into formulating the best feed for your specific fish species and farming conditions.

Proper attention to fish nutrition will contribute significantly to the success of your aquaculture venture.

The harmful effect of overfeeding

·         Over fertilization (water pollution which will need flushing) water turns dark green and suddenly black.

·         Surface scumming: (water flushing and removal of mat like material with basket)

·         Surface reddening: (water flushing and reduction in plant protein in the feed)

·         Surface frothing: (which will require stoppage of fed in use).

Farm infrastructure maintenance

Fish farm infrastructure is either pond(s) or concrete fish tank(s). These are the structures that must be maintained to reduce the high level of depreciation that can lead to water loss or fish loss.

Items of maintenance are as follows:

Weekly general vegetation cleaning is essential.

·         Filling of cracks, fissures, and substances in dams.

·         Repairs of eroded dams and dykes.

·         Checking and repairing pipes and outfalls.

·         Repair of wire fencing or bamboo fencing to deter predators.

In the case of fish tanks

·            Repairs of damaged outlets or pipes or control values

·            Repairs of top covering nets.

Remove scams floating on the water surface by using outlet pipes.

·            Repair of leakage around pipe/block wall joints.

·            Repair of inlet pipe works/shower rose system

Fish farm Security

Fish farm security must be provided in all cases to prevent losses.

·            Wire fencing (with chicken wire and pole) to deter people.

·            Fencing of the entire fish farm from poachers, saboteurs, vandals etc.

·            Use of security guards (day and night hours) as appropriate.

·            Use of traps for reptiles in wetlands around the farm premises.

Fish marketing.

Fish marketing entails the set of activities engaged in for obtaining the best prices and possibly the greatest profits from the sales of fish.

Fish is mostly sold in the following forms:

i.            Fresh lives live in kilos.

ii.            Frozen fresh: (preserved fish) in kilograms

iii.            Smoked (processed fish): sold in pieces

Feed formulation note

A safe formulation must total the intended batch weight and be checked for crude protein, energy, essential amino acids, minerals, vitamins, ingredient quality and species/life stage requirements. Use a qualified aquaculture nutritionist or a validated formulation tool before manufacturing feed commercially.

Conclusion

Remember, fishpond construction and management require ongoing effort and dedication. Seek advice from experienced fish farmers or aquaculture experts to ensure a successful and sustainable fish farming venture.

Disclaimer

This article is intended for farm education. Pond engineering, water quality management, stocking and feed formulation should be adapted to the site, species and production system with advice from qualified aquaculture, fisheries, nutrition or engineering professionals where appropriate.