7 Fish That Breathe Out Of Water
The most common is that fish do not breathe out of water, as most take advantage of dissolved oxygen in the aquatic environment to use it in their metabolism, without having to leave their environment. However, moving on land is another possibility, so there are many fish that breathe outside of the water.
Dissolved oxygen in water is highly dependent on temperature and the presence of aquatic plants that produce it. Normally, the water enters the fish’s mouth through the gills and is expelled, an act with which it tries to retain this gas in the body.
The gills are a thin membrane with tiny holes that capture only oxygen molecules, thanks to a chemical process known as ‘osmosis’. Next, we’ll introduce you to 7 fish that breathe out of water and that challenged the limits of their ancestors.
Many years ago…
At the beginning of the Devonian Era – almost 400 million years ago – most fish species had lung-like organs that, in later species, evolved into swim bladders, whose purpose was to control buoyancy.
Many of these fish moved using fleshy fins. They are believed to be able to support their body weight while crawling underwater, according to the National Wildlife Federation.
However, some of these fish used their lungs to breathe air and their fins to walk on land. Over time, these creatures adapted more and more to terrestrial life, giving rise to amphibians – land animals with fully developed legs – and then to reptiles, dinosaurs, birds and us, humans.
However, this evolution did not develop along the same path in all species. Today, there are numerous amphibian fish that thrive along marine shores around the world.
Some scientists believe that these ‘terrestrial fish’, capable of surviving in the air for long periods, provide clues to the mystery of how vertebrates first invaded the land and how the evolution of land conquest by aquatic animals might have been.
Amphibian fish, fish that breathe out of water
Amphibian fish show how breathing air can be beneficial to those who live in dry or low oxygen waters. These animals have the advantage of expanding their diet, using the land as a refuge against other marine creatures and surviving exposure to air when they are dragged to shore or trapped in shallow water.
The success of the first species of fish on land depended, in part, on how long they could breathe out of the water. The longer the range, the better were your chances of avoiding specific predators or finding cooler water.
When today’s amphibious fish land, they often use their gills to breathe. The gills of amphibians are larger than those of purely aquatic species. The larger size of these structures facilitates the ability to capture oxygen from the air.
However, there are amphibian fish that have lungs to breathe and others that suck air through their mouths and expel it through their gills. Here are some examples.
7 fish that breathe out of water
Fish that breathe out of water required evolutionary adaptations in sense organs such as the skin and eyes. For example, purely aquatic fish do not have the ability to see out of water, just as we cannot see underwater. In addition, these fish have also adapted the way they can breathe.
1. Clinocottus analis , the green-blooded fish
This fish is native to the eastern Pacific Ocean, where it is found along the coast of California and Baja California. It reaches up to 18 centimeters in length, can live up to 18 meters deep in rocky intertidal waters and is able to voluntarily leave the water and breathe up to 24 hours outside of it.
This species has green blood plasma. Its color is due to biliverdin strongly bound to protein complexes, according to some studies. When on land, these fish get 71% of their oxygen through the gills and oral membranes and 29% through the skin, which is called ‘skin breathing’.
2. Mud Jumpers, Natural Jumpers
Fish of the Periophthalmus genus – also known as mud jumpers – live in mangrove waters and breathe the air like an amphibian. Fish included in this group are able to breathe through the skin, oral mucosa, pharynx, and large branchial chambers.
They are small amphibian fish from East Africa and China and can survive out of water for up to 2 and a half days. In addition, they are incredibly agile: they climb rocks, jump from one mangrove root to another, and leap over wet banks.
3. Kryptolebias marmoratus , one of the fish that breathe out of water thanks to its adaptations
When tropical waters get too hot, this fish can go ashore, thanks to adaptations that allow it to breathe air. Your skin, for example, fulfills many functions of the gills.
In addition, this species has cutaneous blood vessels very close to the outside. Therefore, the fish is able to absorb more oxygen in the blood, according to National Geographic experts .
4. Catfish, the great walker
This fish has the ability to ‘walk’ long distances on land, according to experts, as it can survive in this environment for hours and even days. However, walking catfish ( Clarias batrachus ) can only stay out of the water with moist skin, which is why it normally travels overland after heavy rains.
In addition, this species has an extra organ, which supports the gills to extract oxygen from the air. He moves through green meadows in search of a companion or food or when his water source is drying up.
Catfish move by flexing its body and thanks to its spiny fins that give it an extra boost. It is native to Southeast Asia, but has been found throughout the United States.
5. West African lungfish ( Protopterus annectens )
In addition to the gills, this fish has a primitive lung, like all lung fish. In times of drought, the specimens are wrapped in a cocoon of mucus buried in the mud and, when the rains return, they leave the ground.
6. Northern snakehead fish
It is an invasive carnivorous fish native to China, Russia and Korea. This fish ( Channa argus ) can breathe air and survive up to 4 days on land. It is able to stay out of water even longer when the environment is humid or muddy. this animal measures approximately one meter and moves on land moving its body across the ground.
7. The unstoppable climber
This fish ( Anabas testudineus ) is native to Southeast Asia and, in addition to its gills, it has human-like lungs that allow it to breathe on land. It can stay out of the water up to 6 days, but it usually hibernates for up to 6 months in muddy environments.
This animal is capable of moving on land, climbing trees and smothering birds and other fish that try to attack it. Experts say that apparently nothing can stop this fish, as it has the ability to survive in both fresh and salt water.
Can fish that breathe out of water evolve?
The National Wildlife Federation says that while the adaptations of today’s amphibian fish give us an idea of how vertebrates got out of the sea and onto the coast, these creatures are unlikely to give rise to future terrestrial species.
The main difference between amphibian fish and the fish that gave rise to amphibians, reptiles and humans is that today there are animals that live on land. Exploring a niche already dominated by other species is not an easy task.
However, these fish are not at a dead end in terms of their full adaptation to the land. It may be hypothesized that if for some reason life on earth were to cease, then there would be the possibility that they would invade again. An evolving insurance policy.
