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?
How do fish breathe underwater?
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.
Why do fish swim sideways sometimes?
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
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.
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.
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.
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?
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 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:
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.