How do I know fish pond design and construction? What are the 4 components of pond construction? How do you design a pond? What are major considerations in pond making? What is the standard size of a fish pond?
There are 2 basic types of pond systems: HATCHERY and GROW-OUT pond system. Let’s have more insights into the hatchery pond system first.
Hatchery/Incubated Pond Shed
This structure though optional could measure 12 by 12 feet or more. It could be constructed with blocks, wooden plyboard planks and a zinc roof so as to shade and protect it from rain, direct sunlight as well as predators and poachers.
This pond could be more than one concrete (constructed with blocks, gravel and cement), wooden or fibreglass pond. The dimension could be 20inches deep, 3ft wide and 8ft long.
Note that it could be smaller or even bigger, depending on your scale of operation. The floor should be made to slope gently, in such a way that the water could easily be discharged from one outlet via a plastic pipe.
This pond could also be more than one concrete constructed with blocks, gravel and cement, wooden or fibreglass pond. The dimension could be 20inches deep, 3ft wide and 8ft long. This can stock 10,000 fingerlings at a stocking rate of 125 fingerlings per square foot for concrete ponds and 100 fingerlings per square foot for wooden ponds.
You can use this stocking rate to determine the size of your own pond: relative to the number of fingerlings you want to hatch and handle or depending on your scale of operation.
How To Construct And Fit Concrete Hatchery/Incubation Pond
- A flat piece of land (level it if it’s undulating) with enough space for the size you wish to construct
- 6 inches hallowed or solid blocks
- Sharp and plaster sand
- Tape, twine or rope, shovel, cutlass, digger, wooden pegs
- Plastic pipes and elbows (half, ¼ and 1inch)
- Filter made from half-inch perforated plastic pipe and white mosquito net sewing thread
Procedure For Constructing The Hatchery/Incubation Pond
- Clear the selected site (if necessary)
- Peg out the desired dimension (3 by 8ft). Use twine or rope to demarcate the pegged area
- Dig up the pond foundation to about 3inches deep and remove the dug-up soil from the site
- Pour foundation concrete using a good concrete mixture of cement, sand, gravel, and water into the ratio of 1:2:4, i.e. one head pan of cement to 2 head pans of sand to 4 head pans of granite to 1kg of pudlo waterproof cement to produce a solid foundation concreted to a thickness of 3inches
- Raise block walls along the 4 sides of the pond using 6inches of hollow or solid blocks. The wall should extend to a maximum height of about 1.2ft above the ground level so as to secure a pond depth of 10inches and a water level of 8inches
- Floor and slope the floor towards the side of the pond from which you desire to drain for easy drainage – possibly one end of the length of the pond, using the same concrete mixture stated above to a thickness of 3inches
- Plaster the inner and outer wall as well as the floor of the pond with a good thick 1inch layer of cement and sand mixture. Mix the ratio of one bag of cement to 6 head pans of sand. Or use the pudlo waterproof cement and allow it to dry slowly with a covering of raffia or jute bags. Wet it twice daily for the next 7 days under a shaded or cool atmosphere
- Build a walled and roofed structure shed over the pond to prevent direct sunlight and rainfall from reaching the pond and also prevent children or animals from encroaching or drowning
- To fix the wastewater discharge pipe, bore a hole through the block in the lower side of the pond, pass a 9-inch length of plastic pipe with a diameter of one inch through the hole and hold it in place with cement mixed with water. Attach a 12-inch length plastic pipe with a diameter of 3 quarter inches to the plastic elbow, a diameter of one inch and finally attach this set to the one attached to the pond once the concrete work is dry
- Use half-inch perforated plastic pipe filter covered with white mosquito net and tied with sewing thread to block the waste discharge pipe already put in place to prevent fish from escaping from the pond
Now let’s move to:
Grow-Out Pond System
As the name implies, concrete ponds are constructed using concrete materials namely blocks, cement, gravel, sand, etc. There are three different types of grow-out pond systems in operation: the stagnant concrete grow-out pond, the free flow grow-out pond and the water re-circulatory concrete grow-out pond systems.
Stagnant Concrete Grow-Out Pond System
This pond is such that the water once pumped in will remain until when you notice that the water is bad before you change the water. This type of pond compared to the other concrete types is cheaper to construct and maintain but in terms of stocking capacity, fish growth and output, it gives the least result, regarding performance, in other words, you cannot stock the same quantity of fish in this pond as you could in other concrete pond systems irrespective of whether they are of the same size.
For example, while a stagnant pond of 10 by 20ft dimension with a depth of 4ft water level can only stock a maximum of between 300 to 600 table size matured catfish, other concrete pond types of the same size could stock between 1,800 and 3,600 tables size catfish.
Similarly, it will take between 6 to 9 months for the fish grown in a stagnant pond to reach the average table size of 0.5kg while on the other hand, it will take between 5 to 6 months in other concrete pond types.
Free Flow Concrete Grow-Out Pond System
This pond system works on the principle that freshwater flow from the water source employed into the pond continuously, while wastewater from the pond flows continuously into a wastewater pit. The wastewater is not refined or reused. It’s allowed to either sink underground or go into a waste pit or gutter.
The running of the water is not necessarily continuously for 24 hours every day. Rather it can be made to run and stopped intermittently every 4 to 6 hours. However, you’ll need to change the pond water by 70% and wash the pond water when necessary.
The major shortcoming of this system is that water wastage is very high in which case it may not be very feasible where constant water availability is not guaranteed.
Furthermore, the entire pond water still has to be removed and the pond washed once in a while.
Besides this, some of the suspended and dissolved wastes cannot be removed from the pond water as such the stocking rate is not as high as that of the re-circulatory system.
These notwithstanding, the grains are tremendous. Firstly, the stocking capacity is nearly equal to that of the re-circulatory system, likewise the growth rate and time, which is fast and shorter.
The cost of construction is equal to that of the stagnant concrete pond.
Water Re-Circulatory Concrete Grow-Out Pond System
This pond ensures that there is complete water refilling and circulation. The principle behind this type of pond system is that there’s high water efficiency.
Water flowing from the elevated water reservoir tanks enters the pond and at the same time wastewater is discharged from the pond into a refilling chamber from where it is passed through a series of sedimentation tanks.
From the last of the sedimentation tanks, the water is then picked up with a pumping machine and then passed through a bio-filter in order to remove all solid, suspended and soluble water reservoir tanks from where the water flows into the ponds continuously.
It could also be directly pumped through the bio-filter into the ponds on a continuous basis.
This pond type is most advanced in terms of water efficiency, stocking capacity, water quality and percentage of dissolved oxygen in the pond water among other attributes and derivable benefits.
But it is the most expensive in terms of construction, fillings and maintenance. You’ll also have to ensure that the entire pond water is discharged and the pond refilled totally fresh or refined water from the ponds once in a while because not all wastes, especially solid wastes can be removed from the main ponds.
These solid wastes easily precipitate and stick to the pond base over time. As such, they cannot be removed through ordinary water flow, hence the need to be scrubbed and removed from the ponds so as to prevent the decaying organic wastes from polluting the ponds.
Nevertheless, the output outweighs the cost and maintenance implications. This is because the stocking capacity is higher, fish growth is faster, the harvest period is shorter and water consumption is lesser, for instance, a re-circulatory pond of about 10 by 20ft dimension with a water level depth of 4ft could stock comfortably between 1,800 and 3,600 table size catfish with a maturity period of 5 to 6 months which is relatively higher with a better output compared to the stagnant pond system.
Procedures For The Construction Of Earthen Pond System
Since the space for the earthen pond system is most likely to be available and cheap in swampy areas of towns, cities or villages, I recommended that the minimum dimensions of your earthen pond should be 20 by 40ft.
That will enable you to reap immensely from the economies of space which is a combination of high stocking capacity, space reduced incidence of cannibalism and rapid growth of fish amongst other benefits.
This pond size for instance depending on your choice can stock between 5,000 and 8,000 adult catfish of an average size of 0.5kg.
- Clear the selected site and remove all trees and shrubs and their branches
- Peg out the desired dimension and use rope to demarcate the pegged area
- Dig up the soil to about 1.5ft deep and remove the dug up soil and use it to construct the dyke around the pit. The dug up stumps of trees should be removed from the site
- Compact the dyke walls of the pond by compounding it with a log of wood or trampling it with your feet
- Slope the floor of the pond gradually towards the lower side of the pond for easy drainage
- Use iron rods, sticks, and mosquito/fishnet to construct a fence around the perimeter of the pond on top of the dyke. (This is optional)
- Fence the pond – if possible – to prevent children or animals from drowning in the pond. Use blocks, bamboo or other useful materials.
- Plant vegetation, especially plantains around the pond to serve as a shed for the fish during the high midday sun
- If the underground water is not sufficient then dig a well or construct a borehole to serve as an alternative water source
- Construct one or two small ponds for sorting and grading purposes
After constructing the pond and the dyke, put in garmalin 20 (optional) as soon as water flows into the pond so as to kill all available predators in the water.
Thereafter, cover the entire pond surface with a fishing net. After 2 days remove the net, pump out the entire water in the pond and ensure that the pond is dry.
At this point, you can lime and fertilise the new constructed earthen pond. You could apply the lime on the pond floor before filling the pond with water or put it in a sack and place it by the side of the pond before filling the pond with water or put it in a sack and place it in the water in-let.
- Powder limestone
- Caustic lime
- Calcium hydroxide
- Quick lime
The caustic lime or the quick lime should be applied in smaller quantities, immediately after that, cover the pond again with a net so as to prevent predators from gaining access to the pond.
You will need to leave the pond for at least 7 to 14 days before stocking.
Importance of liming the pond:
- Correction of water and soil PH
- Elimination of water diseases and promotion of nutrient release by breaking down organic matters
Lime your pond at least once every 2 years thereafter, with a limited quantity of calcium hydroxide or limestone. As for fertilisation, follow any of the methods listed for concrete ponds.
Cons Of The Earthen Grow-Out Pond System
The major problem associated with the earthen pond system is security. If fencing or security is not employed you may lose all your fish to poachers.
Furthermore, the pond may not be easily accessible during the rainy seasons, especially in waterlogged swamps.
In this case, you may need rain boots and waders. Flooding is another constant worry, especially during the rainy season.
These can seriously undermine your investment if not effectively controlled as it may lead to fish escape, pond water pollution, pond collapse, etc. You may also have lesser effective control over the fish because of the size of the pond.
In order to evacuate water from the pond, you must use a petrol-powered pump. Sorting through which is very important is also very cumbersome.
Sorting fish at 6 regular intervals in order to separate shooters (faster-growing ones) from the rest so as to avoid cannibalism is a bit taxing because you have to pump out the pond water completely on each occasion.
Besides, you may not be able to sort out all stages and the fact that most will hide in the mud and later surface to cause some major havoc (feeding on the smaller ones) thereby reducing your stock. Nevertheless, the advantages are many.
Pros Of The Earthen Grow-Out Pond System
- It’s relatively cheaper to construct and manage
- You have the capacity of a very large stocking rate
- Fish growth is very rapid and the size is bigger due to the natural environment, space and air
- Profitability is higher because higher stocking capacity coupled with other factors help to reduce the unit cost of raring a fish
- Land is cheap and the environment more conducive to aquaculture – fish farming – because such sites are located in rural communities or suburbs of towns and cities
Having analysed the various fish pond systems, I advise you to think it through and consider which of them you’ll prefer to operate by considering the following:
- The size of your investment capital
- Whether you want to do it full or part-time
- What basic resources – land, water, electricity, etc. – do you have in place?
- The size of your operation – small, medium or large scale
- Ability to stock them with fingerlings, etc.
Pond Preparation And Stocking: Concrete Ponds
On completion of all ponds construction works including installation of fittings and plastering, allow the pond to dry completely for 5 to 7 days.
After which you can pump water into the pond and wash it thoroughly to remove excess cement on the surfaces of the walls and floor. Thereafter, pump clean water into the pond and fertilise it using:
- Poultry wastes: put it into a sack, tie the mouth and put it into the pond for 3 days. At the end of the third day, remove the sac. By so doing the water would have been fertilised and ready for stocking, but you have to leave the pond for another 4 days after removing the poultry wasted sack before stocking with fish
- 72% fishmeal: apply the same process as poultry wastes’ but it has to remain in the water for exactly 7 days before stocking the pond with fish after removing the sack
- Artificial fertiliser (NPK 20, 20, 20): spray the fertiliser over the pond and leave it for a minimum of 7 days before stocking it with fish. Irrespective of the type of pond you choose to use. Make sure that the pond is covered at this time – from the moment water is introduced to the moment the water is fertilised – with a mosquito net to prevent predators from entering the pond and lying in wait for the fingerlings. All these are for the concrete pond system and do not lime concrete ponds
Alternatively, you may not need to fertilise the concrete ponds because the fish is intensive and so the waste palliated feed concentrates in the pond will help fertilise the pond water, making it appear greenish in colour.
Those are the basics of fish pond design and construction. Please note that there are other types of ponds that are cheaper such as tarpaulin ponds, tank ponds, etc. I may not be able to write on every one of them in this article.
In part one of my series, I already discussed the profitability of the catfish farming business in Nigeria, in my next series, we shall be giving you more insights into HATCHERY TECHNIQUES/PROCEDURES OF REPRODUCTION. See you at the top.
This article was most recently revised and updated on April 4, 2022