While it may not be so obvious in the case of fish as it is in humans, all aquatic creatures need oxygen to stay alive. Unlike the air we breathe as land-dwelling beings, fish rely on the oxygen diluted in the water they reside in for their needs. Natural water bodies such as lakes, oceans, and rivers have natural mechanisms to maintain sustainable oxygen levels.
Artificial structures such as ponds and fish tanks need some help in this regard, as none of the natural mechanisms found in nature exists here. The need for oxygen in fish farming is addressed by various oxygenation and aeration measures that help bring up the oxygen levels in these structures. As the amount of oxygen in aquaculture setups directly affects the fish population’s number, size, and health, it is a vital consideration for fish farmers.
In this piece, we’ll be looking at some of the more common and effective ways to oxygenate or aerate a fish pond.
What Causes Low Oxygen Levels in Pond Water?
Several factors may cause depletion of oxygen in pond water including:
- Respiration of Aquatic Plants: While aquatic plants such as algae and planktons add oxygen to pond water through photosynthesis, they also consume oxygen during the night when there is no sunlight. This can cause the oxygen levels in the water to drop.
- High Water Temperature: Increased pond water temperature, particularly during the summer, causes the decomposition of organic wastes in the water. This process can significantly reduce the amount of dissolved oxygen.
How To Tell If Oxygen Levels Are Low in Pond Water
Some signs of depleted oxygen in pond water include:
Remember, even if your pond doesn’t exhibit the signs mentioned above of oxygen depletion, it is still advisable to regularly oxygenate your pond. Having high oxygen levels in your pond significantly improves the conditions for your fish by promoting better aeration and filtration and facilitating the growth of healthy bacteria.
Difference Between Oxygenation and Aeration
While these two terms might seem interchangeable at a casual glance, there are distinctions between those carrying out commercial fish farming. Oxygenation can be said to be an aspect of aeration. It is the process of infusing large quantities of oxygen directly into the water and is achieved by using oxygen pumps, oxygen diffusers, Low-Head Oxygenators (LHOs), etc.
Aeration, on the other hand, provides not only oxygen but water movement in the water. This movement helps circulate nutrients and encourages oxygen transfer from the open-air into the water. Water with no movement will quickly become stagnant, which does not support fish life and provides breeding grounds for mosquitoes. Natural aerators include fountains, pond plants, solar-powered air pumps, or even your typical garden hose.
4 Ways To Oxygenate A Commercial Fish Pond
Now, the oxygenation of fish ponds for commercial aquaculture needs significant oxygen concentration levels, as farmers aim for maximum returns on their investment. This necessitates the use of powerful oxygenators such as:
1. Air Pumps or Blowers
These precise units draw air from the atmosphere and redirect it into the water. They are placed next to the fish pond and started up, at which point the air they push through a hose into the water will inevitably rise in the water and break on the surface.
When they break the water’s surface, oxygen will be added to the pond. A little-known advantage of having an air pump for your aquaculture setup is that it will act as an ice tool for prevention during the winter months, preventing the complete covering of your pond under the ice.
2. Low Head Oxygenators
An LHO works by drawing out nitrogen from the water around it and replacing it with oxygen. A good unit can get its oxygen absorption efficiency levels to 95%, which is why large-scale aquaculture setups prefer such units. The fact that they do not use electricity for their operation is another feature that makes them popular with fish farmers.
3. Oxygen Cones
Large-scale aquaculture operations will need some heavy-duty solutions for their oxygen needs. Oxygen cones are up to this task. They are pressurized vessels with unique bottom outlets that allow external connections without occasional hydraulic interruption. Interruptions may come about due to their typical snorkel pipe design. Such units provide exceptional oxygen dissolution, although they can be adapted to deliver ozone rather than oxygen.
4. Natural Pond Plants
The available solutions for those hoping to increase the oxygen content of their ponds don’t necessarily need to be mechanical. Plants generate oxygen through the natural process of photosynthesis, which might provide a natural, low-cost way of increasing the dissolved oxygen levels in your pond.
Aside from providing oxygen, submerged plant types such as the Hornwort will also absorb waste from the water (mainly phosphates and nitrates). Nuisance algae will thus be denied this fertilizer, effectively helping keep their spread at minimal levels.
What is The Optimal Level of Oxygen in a Fish Pond?
In general, oxygen levels in fish ponds are much lower than the oxygen concentration in atmospheric air. Rarely do ponds contain more than 10ppm (parts per million) compared to the atmospheric oxygen concentration of 200,000 ppm. Nevertheless, anything lower than 2 to 3 ppm oxygen concentration is hazardous to the lives of aquatic animals, including fish.
While the appropriate oxygen level of a pond varies depending on the size of the pond and fish population, it is advisable to have at least 6mg per liter of water in any pond.
Billions of people worldwide rely on fish to provide a significant segment of their diet, meaning they wouldn’t be able to meet their nutritional needs without it. Consequently, the world’s oceans, lakes, and waterways are becoming increasingly overfished, decimating fish populations and presenting the risk of extinction for some fish species. It is unsustainable, and the global fishing industry seeks a new way of doing things.
Aquaculture and commercial fish farming is a viable and sustainable alternative to traditional fishing practices, and farmers need to be well-versed in the importance of oxygen in fish farming. Different aquaculture operations will call for different solutions, so take the solutions we’ve covered here as a starting point as you seek out what will work best for you. Best of luck!