Top 6 Ways To Avoid Mortality in Your Fish Farm.

Every fish farmer is looking for ways to increase their profit margins, but with your fish dying, how can you make profits? Today, we discuss the top 6 ways to avoid mortality in your fish farm.

If you produce fish at any level, be it catfish, tilapia, or salmon, in any type of pond, mortality or the death of your fish is something you would deal with at some point. It can be extremely hard to pinpoint what is going wrong until you have lost a couple of your fish.

In this article, our goal is to show you the top 6 ways to avoid mortality in your fish farm and to ensure continues profits are generated by your project.

Some farmers have reported losses in excess of tons of fish overnight, so if you are experiencing a mortality or death of your fish, you should pay good attention to these top 6 ways to avoid mortality in your fish farm, and apply them with utmost precision to stop your fish from dying.

Catfish are better able to withstand higher myriads of conditions compared to tilapia, because of it’s tough nature, some farmers may not pay attention to its survivability, but know this, we have personally experienced a loss of over 1 ton of catfish due to hypoxia resulting from intensive use of duckweeds in the pond.

Regardless of the type of fish you grow, you can equally benefit from the top 6 ways to avoid mortality in your fish farm.

Yes! Excessive duckweed growth, led to oxygen depletion that resulted in death of over 650 catfish all weighing above 2 kg in an earthen pond. We will expand on this to help you get a better understanding of this situation with the hope that we might save at least one farmer from such massive losses.

What Do Fish Require For Survival

  • Appropriate water pH levels
  • Appropriate dissolved oxygen
  • Fish Feed
  • Bio-Safety (Absence of predators)
  • Temperature
  • Ammonia Concentration

What Ph Levels Is Best for My Fish

pH is a reference figure for the acidity or alkalinity of a given medium, in this case water. Each fish have different ranges of pH that they can survive in, any pH below or above can trigger mortality among your fish and cause your fish to die.

What Ph Levels Is Best for My Fish, What Do Fish Require For Survival, Recommended Ph for Catfish, Tilapia and Salmon, Top 6 Ways To Avoid Mortality in Your Fish Farm.

You can stop your fish from dying from bad pH by checking the pH of the water in your pond on a regular basis.

Fish farming is capital intensive, as such assumptions can be very risky and could lead to huge losses.

Recommended Ph for Catfish, Tilapia and Salmon

Type of FishRecommended pH
Catfish6.5 – 7.5
Tilapia7.0 – 9.0
Salmon7.0 – 8.0
Type of Fish, and their recommended pH

Working to maintain these pH levels is a daily recurring activity, a little mistake, error or over sight could result in huge losses.

The type of pond you use could help or contribute to rising pH levels, while earthen ponds have been known to serve as a good buffer, it can equally have bad pH levels.

Most fish, prefer netrual to basic pH levels, however, introduction of fish feed, and the excretion of their own waste means that it is next to impossible for a pond to remain neutral pH without your support as a farmer.

How To Prevent pH Levels From Becoming Toxic to Your Fish

  1. Stock the right quantity of fish. Overstocking a pond means more feed, and more waste, which in turn increases the water pH of your fish pond. If you grow catfish, use our stock density calculator to determine the accurate number of fish to stock.
  2. Avoid over-feeding your fish. Fish are smart, once they are satisfied, they would not eat the remaining feed. These feeds descend into your pond, rots and contribute to rising pH levels of your fish pond.
  3. Test your water regularly and change the water regularly to reduce the chances of acidic build-up in your pond!
  4. Introduce duckweeds or Azolla in your pond, these aquatic plants, would consume excess nutrients and help reduce the chances of acid buildup in the pond.

What To Do If Your Water pH Levels Are Too High in Your Fish Pond.

Ideally, you do not wait till the pH is too bad before you take action, however, factors such as over stocking, over feeding, and nature of pond can quickly contribute to bad pH in your fish pond.

If you notice your pH levels are terrible, quickly change the water in your pond. Pump out about 2/3rd of the water in the pond and quickly replace with fresh water.

How frequently the pH rises, forcing you to change your water depends on the type of pond you use.

For example, earthen ponds can maitain pH levels much higher than concrete ponds or tarpulin ponds.

Dissolved Oxygen

Oxygen is crucial to life in the fish pond, without it, all your fishes would die in a matter of minutes. You can prevent your fish from dying by making sure your water is properly oxygenated.

Physically you can observe your fish to determine if the oxygen levels are diminishing or not. When more and more fishes come up to gasp for air, it is a sign that danger is looming and your fish may be lacking oxygen.

Any fish pond with little to no oxygen is a disaster waiting to happen, but how can your pond water have no oxygen?

Factors That Causes Oxygen Depletion in a Fish Pond

  1. Duckweeds or Azolla; when we wrote about the 4 ways you can reduce your cost of production in your fish farm, we recommended the use of duckweeds, however, when the entire surface of the pond is covered with duckweeds, they will extract more oxygen from the pond than they are able to replace.

    When the surface of the ponds is covered as well, they do not allow for the exchange of gases through diffusion to take place, further depriving the pond of oxygen.

    If you are to keep your fish and duckweeds in the same pond, we recommend you ensure the duckweeds do not cover more than 2/3rd of the surface of the pond, ideally, grow your duckweeds in a separate pond and introduce them daily to the fish to prevent the death of your fish.
  2. Other causes of oxygen depletion in a pond include lack of aeration, cloudy weather and wind mixing the pond, and overstocking which further leads to increased demand for oxygen in the pond.

How To Prevent Oxygen Depletion in Your Fish Pond.

  1. Avoid Over stocking your pond
  2. Use aerators to continuously introduce oxygen into your pond.
  3. Use Floating Vertical Propeller Pump Aeration to prevent the water from being still. The more aggressively the water moves about, the better it is able to exchange gases and introduce oxygen into the pond.
  4. Use minimal amounts of duckweed, Azolla, or algae in the pond to help introduce oxygen into the pond. Note; too many duckweeds, Azolla, or algae can actually lead to oxygen depletion. Never let it cover more than 2/3rd of the pond surface.
  5. Frequently change your water.

Fish Feed

After all is said and done, your fish must eat! Like yourself, without food, hunger would consume you.

You can stop your fish from dying by feeding them regularly. Fish like Catfish are predatory in nature. If you fail to feed them, they would attack the weaker ones and kill them for a meal.

What is worse for Catfish is that they can kill their own, eat it and you might not have any trace of this at all.

Without properly feeding your fish, you can stock 10,000 fingerlings but at harvest, you might be lucky to even have half of them present.

If you produce catfish, we recommend to you 6 best ways you can reduce mortality among your catfish.


You want to prevent your fish from dying, you might want to take your bio-safety seriously.

Malicious neighbours can come and poison your pond, whats your security to that? Whats more predators like snake, tortoise, lizards, birds, frogs etc. are known to have wrecked havoc to many fish colonies.

Ensure your fish pond is adequaltely protected from all these forms of predators. Physical barriers are crucial in this regard.

A single frog can consume over 1000 fingerlings of fish if you do not identify and eliminate it.


The temperature of your fish pond is crucial to the survival of the fish in it. Be sure to know the specific temperatures that your fish can survive, and the optimum for their growth to ensure you have the best results.

types of fish and their recommended temperature for growth, What is the ideal temperature for catfish, what is the ideal tempeaature for tilapia, what is the ideal temperature for salmon

How To Avoid Excess Temperature in Your Fish Pond

  1. Consider the nature of your pond; Earthen ponds are better able to regulate temperature than other pond types.
  2. Consider the size of your pond; Bigger size ponds are better able to regulate temperature than smaller size ponds
  3. Include a shade in your pond design, a shade covering at least half the pond could reduce direct sunlight and thus help regulate the temperature.
  4. Take into consideration the average temperature of your site in choosing what type of fish to grow.
  5. Use aquatic cover crops like duckweeds for at most 2/3rd of the pond.
  6. Avoid an idle pond, use floating verticle propeller pumps to keep the water in the pond moving in waves.
  7. Where all else fails, consider growing the fish in the lake or the sea or other large water bodies.

How to Deal with Ammonia Concentration in Your Fish Pond

Ammonia is toxic to your fish, they come about from excretion of the fish and the feed you provide your fish.

Excess ammonia in your pond could result in uncontrolled algae growth, lower levels of dissolved oxygen and general slow growth of your fish.

The best way to deal with this is to;

  1. regularly change your water
  2. Avoid over feeding
  3. use of aquatic plants that feed on excess ammonia like duckweeds


Leave a Reply

Your email address will not be published. Required fields are marked *