Can a Fish Drown – How to prevent it from happening?

Can a Fish Drown in Water?

Can a Fish Drown? It is one of the many questions we ask ourselves when we think of Fishes. It might surprise you that a fish can drown. But, this would be termed suffocation or asphyxiation. If, a fish can drown, how to prevent it from happening? Let us continue reading!

 How is it possible for a fish to drown? One of the reasons why a fish can drown where a low or lack of dissolved oxygen level in the water. The other reasons include a change in the pressure and a change in the water temperature.

Fish can drown in an over-populated environment. A fish can also drown due to poor water circulation like in a fish tank, fish pond, aquarium, etc.

 Let us keep reading to know about how can fish drown or suffocate in the water?

What is drowning?

Drowning is defined as respiratory impairment as a result of being in or under a liquid. Which means dying from not being able to breathe in air and breathing in water or another liquid. Consequently, there is more water than air in the lungs. Oxygen is quintessential for fishes to live as any other living beings with the exceptions of anaerobes.

How do fish breathe underwater?

How do fish gills work

Not all the creatures living in the water can breathe underwater. Whales, Seals, Sea Otters, Dolphins, etc. are some examples of animals that live in the water, but cannot breathe underwater, because, their breathing organs are lungs like other mammals living on the land. Whereas, fish, crabs, mollusks, etc. can breathe underwater. Tadpoles, dragonflies, etc. which live in the water at first, also use their gills to breathe. 

Fish get their oxygen from the water. A large amount of water passes through their mouths and gills, whereby the dissolved oxygen in the water passes through the thin walls of gills and into the bloodstream. Thereby, fish absorbs oxygen from the Red Blood Cells in exchange for carbon dioxide. This is possible only when the dissolved oxygen level in the water is higher than the blood.
The desired oxygen level is 5.0 to 6.0 Parts Per Millions(ppm) for any aquarium, pond, or fish tank. When the dissolved oxygen level drops to 3.00 ppm, it becomes stressful for all the aquatic lives. Further, it will become fatal for fish and other aquatic lives when dissolved oxygen drops below 2.0 ppm.
One might wonder why a fish out of the water dies despite the presence of higher oxygen in the air than in the water? Well, the answer is that the gills of fish are not meant to process air.
Apart from gills, fishes have other breathing channels.  The babies breathe through their skin before the gills form. Although, about 10 to 20% of the breathing takes place through the skin of an adult fish.

Why do fish swim sideways sometimes?

Can Fish Die from Swim Bladder Disease

This is caused by Swim Bladder Disease. The causes of Swim Bladder Disease are:

  • Constipation through over-eating (Overfeeding).
  • Gulping of air while grabbing their prey at the surface of the water.
  • Lower Water temperature (below 80 degrees Fahrenheit can result in a slower metabolism and can lead to various diseases.
  • Inflamed organs are another main cause of Swim Bladder Disease.

Can a fish drown if pulled backward?

This may be true for some species of fish. If the fish is pulled backward it can suffocate and die: The gills of fish work only one way as the water passes over its gills in reverse. 

The one other reason why fish drown if pulled backward is selective breeding. This process is carried out to bring out brilliant colors, large and flowing fins, but this process affects their inner organs that include gills. For example, Siamese fish or Betta‘s natural colors, in general, brown, grey, and green, and the fins are shorter; similarly, the most popular species in the aquarium trade Goldfish’s natural colors are dull grey or silver grey or olive green. Today, there are over 200 types of goldfish in the aquarium trade, all are the result of centuries of cross breedings.  However, in the aquarium business, they have been selectively bred to display a vibrant display of colors, fins, and tails.

Causes of Low Oxygen Levels in Fish Tanks, Aquariums, and Ponds

What causes algae bloom

There are multiple reasons why the dissolved oxygen levels in the water may be low. The most common causes are:

Overfertilization/excess nutrients and excess algae:

Overfeeding the fish results in excess bacterial concentration in a closed atmosphere which leads to depletion of oxygen. Depletion in the oxygen level can drown fish/suffocate a fish.

Over Crowding:

Similarly, overpopulation in a confined environment like in a fish tank, fish pond, or an aquarium leads to reduced oxygen level that causes fish to drown/suffocate.

Diseases and Parasites:

Like humans, fish suffer from diseases and parasites. According to Wikipedia, Disease is a prime agent affecting fish mortality, especially when fishes are young. Also, Parasites in fish are a common natural occurrence.

Low light levels:

Generally fish requires less light, unlike plant kingdoms. Photosynthesis of plants can take place only when there is balanced light. Photosynthesis determines the level of dissolved oxygen in the water. Thus, the fish tank requires 10 to 12 hours of lighting.

pH off balance:

If the pH of the water in the aquarium is too low will kill most of the ornamental fishes and the eggs in the aquarium. If it is too high, it will shoot up algae matter and induce depletion of dissolved oxygen level in the water.

Elevated temperature:

When the temperature of the water goes, the metabolism of the fish speeds up, in turn, they use more oxygen. However, when the water temperature rises it holds less oxygen. Hence, the fish can drown or suffocate due to low-level oxygen in the water. 

Decomposed Plants:

Decomposing green matters absorb a high level of oxygen resulting in the deprivation of dissolved oxygen in the water.

Lack of circulation of water:

Stagnant water has a low oxygen level. Water movement significantly improves dissolved oxygen levels in the water. Filtration moves water and thereby distributes oxygen homogeneously in the water tank or an aquarium.

How do we know if the Oxygen Levels are low?

A fish living in a tank or an aquarium, wherein the dissolved oxygen level is low will exhibit numerous signs, such as:

  • lack of movement or minimum movement
  • Heavy and difficult breathing
  • Staying around the surface of the water and gasping
  • Moving gills rapidly
  • Eating less or not at all

How to prevent a fish from drowning in a tank or an aquarium or a pond?

How to get more oxygen in fish tank

The fish does not breathe oxygen molecules of the water. They breathe dissolved oxygen in the water. Then, it is essential to maintain adequate dissolved oxygen in the water. As we have already mentioned in this article, the desired level of dissolved oxygen is 5.0 to 6.0 ppm.

A fish living in an environment where the dissolved oxygen level is below 2.0 ppm becomes fatal to your fish.

Let us look at the preventive measures:

Do not overpopulate:

As we have seen earlier in the article, overpopulation of aquatic life will deplete the dissolved oxygen level in the water, which results in the drowning of your fish.

Bigger Size Tank:

Most of the air exchange takes place at the surface of the water. So, it is wise to choose a tank with a large surface area, which eventually leads to a higher dissolved oxygen level in the water.

Filtration system:

Filtration and Circulation of water in the fish tank is a pre-requisite to:

  • maintain the desired level of dissolved oxygen in the water 
  • reduce the level of decomposing green materials which absorbs a considerable amount of oxygen by oxidation
  • reduce parasites and diseases
  • remove the coagulated substances resulting from the chemical reaction in the tank.

Usage of Chemicals:

Water quality in the fish tank or an aquarium gets deeply affected due to various addition of chemicals.
Cities under the guidance of the World Health Organization (WHO) use some chemicals to disinfect at different stages of water distribution. Chlorine, chlorine dioxide, monochloromine as primary disinfectants and residual disinfectants. Also, coagulants such as aluminum and iron salts are used by most city water distribution.
Therefore use a de-chlorinator to clean any water before adding it to the fish tank. Read thoroughly the instruction and avoid overdosage of any chemicals.

Add Live Aquarium Plants:

The lustrous green and red live aquariums plants certainly add vibrancy and colors to your aquarium tank; they also clean and fix dissolved oxygen in the water.

Live plants such as java moss, java fern create a great cover for shy and timid species and provide shelter to the newborns and housing infusorian, the first fry food.

Adjust the pH of water in the aquarium:

Acclimatize your fish tank, aquarium or pond, every single time you introduce a new fish into them. Most freshwater fishes do well in neutral pH water. The pH of aquarium water will change within a course of time due to the decomposition of organic matter. The best way to tackle this issue is by a regular topping of water.

Adjust the temperature of water:

Higher water temperature increases the metabolism of the fish but diminishes oxygen holding capacity. Therefore, fish can drown or suffocate. Whereas the cold water holds the oxygen, but, diminishes the metabolism.
Hence, it is crucial to maintain the right temperature. The best temperature ranges from 75 and 80 °F (24 to 27 °C) for freshwater or a  tropical fish tank.

To Summarize:

Technically speaking, a fish can’t drown in water, but they experience the same as drowning while suffocating or during asphyxiation. We can prevent it from happening by maintaining the right temperature, a good oxygen level, a balanced pH, and a chemically balanced clean water. Most of all, avoid overfeeding and keep the water crystal clear. You can go a long way in managing your aquarium by keeping your tank clean and providing ample oxygen.
If you have any questions or doubts or would like to share your thoughts about this article, please leave a comment below or contact here.

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