Putting a fish net on a top of a concrete tank is necessary because it serves as a way of protecting the fish against predators like hawk, frog, toad etc in any case, if you must put a fish net, it is better to use chicken net and not mosquito net so that the fish can have adequate access to fresh air.
Fish nets are the subject of very careful selection. Their quality must be beyond reproach since the security of the fish stocks depends largely on the net strength. Mesh size must be adapted to the fish size and. must not allow the fish to trap itself by the gills.
On the other hand, small size mesh is subject to fouling which restricts the water flow through the cage. Fish nets are sold by weight and, therefore, those fish nets with a small size mesh are more expensive.
Large farms will also invest in fish net-washing equipment, which imposes the need to have cages with adequate net-removal facilities.
Concrete ponds are used for intensive fish farming; concrete walls/banks eliminate erosion due to currents caused by mechanical aeration, waves generated by the wind and fish activity (notably nesting behaviour).
This type of pond is more expensive to build and, therefore, should be made profitable by a higher production per volume utilised. Conversely, the firmer walling reduces maintenance and re-building costs that will be necessary after a few years of operation,
This type of pond is smaller than earthen ponds and should not exceed 1,000 m2 surface area. The bottom can also be in concrete but for reasons of construction costs, only if the pond size does not exceed 200 m2.
Brick or stone walls must have strong foundations and, if they are built with bricks or blocks, they must be plastered, in order to avoid the effects of erosion.
Aside Using Fish Net, Here are 7 Tips to Keep Your Fish Pond Water Clean
1. Maintain a healthy fish population
If you have more than 10” of fish for every 100 gallons of water, your pond is likely over-populated. Excessive fish waste can cause an imbalance in pond water. Consider finding some of them a new home. Many pond retailers and contractors will accept your fish.
2. Don’t over-feed your fish
When you feed fish more than they can eat, the uneaten food is left to decay in the pond. Be careful not to feed your fish more than once per day, and no more than they can eat in 2 to 3 minutes. Choose a quality fish food – preferably one that floats as opposed to sinking to the bottom of the pond if left uneaten.
3. Create a proper balance of plants
At season’s peak, you should have 40% to 60% of the surface area of your pond either covered or shaded by plants. Too many plants can cause oxygen deficiencies at night due to the photosynthetic process, when the plants take in oxygen and give off carbon dioxide. Your fish need the oxygen to survive (see tip #7).
4. Choose the right size pump for your pond
You should be circulating the entire pond’s water volume a minimum of once every hour. Make sure your pump’s flow isn’t restricted by debris in the skimmer or biological filter, and be careful not to pump water higher than it was intended. Every pump has its flow limitations.
5. Clean debris from pond before it has a chance to decay
Your pond skimmer will remove most of the debris from the surface of your pond, but you can also use a pond net to skim leaves and small sticks before they have a chance to descend to the pond’s bottom where they’ll decay. Decaying debris, combined with fish waste and leftover fish food, can cause ammonia levels to spike in your pond.
Ammonia can be harmful to your fish and should be addressed right away. If you see your fish jumping out of the water, you likely have an ammonia spike which can happen after adding an algae treatment. You can purchase an ammonia test kit at your local pet and aquarium store and if you find the levels are high, simply treat your pond water with Ammonia Neutralizer.
Beneficial microbes such as Aquascape Beneficial Bacteria helps keep your pond water healthy and clean for your finned friends. Better yet, install an Automatic Dosing System to electronically dispense beneficial bacteria and other treatments to your pond to help with breaking down debris and maintaining a proper nitrogen cycle.
6. Choose proper filtration for your pond
Just like your pond pump, your pond’s filter should match the size of your water garden. Most pond filters are based on ideal circumstances, and if you exceed those, your filter becomes less effective. Always up-size your filter so that it can handle more than the capacity of your pond and remember to clean your filter according to instructions.
There are two types of filters in an Aquascape ecosystem pond. A mechanical filter, also known as the skimmer, removes surface debris from your pond water such as leaves and small sticks. The biological filter, or BioFalls filter, is positioned to create the beginning of the waterfall in your pond. This filter uses bacteria to break down pond wastes, converting them into less harmful compounds that can be absorbed as fertilizer by your aquatic plants.
7. Keep your pond cool during the dog days of summer
When pond water exceeds 75º Fahrenheit, it has a difficult time retaining acceptable levels of dissolved oxygen, which is critical for the health of your fish. This is why it’s important to have the surface of your pond shaded by aquatic plants (see tip #3) to help keep pond water cool. Fish need oxygen to survive. If you see them at the pond’s surface gasping for air, add an aerator to help them during times of extreme heat.
Here are some amazing fish farming books to assist you further and help you get started: