Can Fish Drown? How Do Aquatic Animals Suffocate in Water?

Humans are not the only members of the animal kingdom that can get drowned. Dogs, birds, snakes, and other species can drown when caught in water without means of escaping.

Many people, especially those who own aquariums, claim that fish can drown, but most may not be sure how it happens. If fish can only live underwater, then how do they drown?

What Causes Drowning in Animals?

In both humans and animals, drowning occurs when subversion in liquid leads to suffocation or interferes with breathing. During drowning, the body is deprived of oxygen, which can damage organs such as the brain.

When an animal drowns, the body's carbon dioxide level increases, which triggers it to take a breath. By doing so, the alveoli, the tiny sacs in the lungs responsible for exchanging carbon dioxide and oxygen, get filled with water. These sacs collapse, leading to decreased oxygenation, infection, pneumonia, and organ damage.

Can Fish Drown?

Just like terrestrial animals, aquatic animals also need oxygen to live. While the former get oxygen from the air, the latter live off dissolved oxygen in the water.

Most fish breathe when water moves across their gills, but if these organs are damaged or cannot move across them, the fish can suffer from suffocation. Since fish do not inhale water, they do not technically drown but die from lack of oxygen.

There could be many reasons why this happens. Fishing equipment, such as hooks, can damage the gills. Pathogens like bacteria can also get attached to the gills and block them, preventing these organs from filtering oxygen from the water or degrading them to the point where the gills no longer work.

Some fish can pump water across their gills while at rest, but many must swim constantly to allow water to flow past them. If the fish get trapped in materials such as fishing nets, they may get stuck and suffocate.

Other aquatic animals like turtles and dolphins get air the way we do - by breathing oxygen from the air. However, they can only do so when they are on the surface. This means that when they get trapped in fishing equipment, they are prevented from going to the surface, making them drown.

In some cases, there are areas of the ocean that do not have enough dissolved oxygen to support fish and other aquatic life. This usually happens when many plankton bloom simultaneously when sufficient nutrients become available. As the plankton use up all the oxygen in a short period, the fish population in the area can suffocate since the water cannot constantly replenish oxygen very quickly.

Additionally, warm water does not hold as much dissolved oxygen as cold water, according to the U.S. Geological Survey. As climate change causes the ocean temperature to rise, dead zones with lower oxygen levels emerge.