Do Fish Have Lungs? Complete Respiration In Fish Explained

Fishes have a very complex respiratory system when compared to land-dwelling mammals.

Fish do not have lungs for breathing oxygen, instead, they use their gills to take in oxygen dissolved in water or air. It goes without saying that the structure of a fish's respiratory system in the sea or any water body is not like the terrestrial animals.

A fish's body houses gills that are, in turn, a house to numerous capillaries. These capillaries can absorb oxygen from the water that passes through their gills.

The oxygen goes through its body and is then consumed for various bodily functions. The body then develops the waste which is carbon dioxide and the reverse process passes the waste out, back into the water.

Read on to discover the new mind-blowing facts about fishes and other marine animals found in shallow and deep waters. Firstly, we will learn about fish and their respiratory system and find answers to the question do they have lungs like mammals.

After that, we will talk about how fish breathe underwater as well as some additional information about it.

In addition, we will explain a few basic concepts of fish anatomy such as how gills work. After reading about how the life of fish flows in the water, also check related fact files on do fish have eyelids and do fish have livers?

Do fish have lungs?

Fishes live in water and as such, their breathing system is rather less suited for breathing on land. Fish get oxygen from the water, using their gills for breathing since they have a gill instead of a lung.

Fish do lack the necessary anatomy to breathe air in the same way that land-dwelling animals on the surface breathe with their lungs, but there are types of fish, like the lungfish and some species of amphibians (e.g., the mudpuppy), that are capable of breathing air when their aquatic habitats dry up during parts of the year.

Lungfish will travel onto land and find moist soil to burrow into so that they can keep their skin wet while they continue breathing oxygen via a modified form of gill respiration, and they lie still in the mud in their cocoons until the rain comes and waters return.

The fish's gills are primarily organs for gas exchange. Oxygen from the water passes through the blood through either a one-way flow (as in most fishes) or by pumping air into the pharynx with muscles (as in lungfish and gar).

Most fish need to move actively through the water to pass oxygenated water over their gills, however many species of fish do not require swimmerets or any other form of propulsion mechanism. Some of the fish species have operculum and do not need ram ventilation.

Fish Species That Have Lungs

A few of the most primitive fishes have lungs and gills such as the lungfish and gar. More advanced fishes that have evolved lungs and can breathe air to varying degrees include the following.

The lungfish can come to the surface and take a breath. They are obligate air breathers like some sea mammals.

The Coelacanth have vestigial lungs in the adult stages. The Coelacanth (Latimeria chalumnae) is found in the temperate waters in the twilight zones between 500-800 ft (151.5-242.4 m) around the steep rocky slopes of volcanic islands. During the daytime, they tend to cluster together in ‘caves’ in submarine lava deposits and come out during the night to feed.

Mudskippers are found in Indo-Pacific sea regions mostly living in estuaries and mudflats. They are known for their ability to walk, climb and skip out of water too. Like any other fish, they breathe through their gills. They can also absorb oxygen through their skin and through the linings of their mouth and throats.

African and South American lungfish (similar to gar), and Australian lungfish all have either paired lungs or a single unpaired organ at the back of the head which is capable of gas exchange. During low oxygen periods, they use buccal pumping as a supplement for respiration.

Although gill breathing predominates during high activity levels, they can also breathe via their lungs.

How do fish breathe underwater?

Fish exchange gases like oxygen and carbon dioxide in the water using gills, a respiratory organ. Gills are made up of thread-like structures called filaments. The membrane of these filaments is folded into many small chambers. Each chamber is filled with blood. This is where the oxygen and carbon dioxide transfer takes place from blood capillaries.

The oxygen from the water diffuses across the thin walls into the bloodstream and carbon dioxide passes back into the water in reverse order. Fishes use their gills to exchange oxygen and carbon dioxide dissolved in the water.

The gills are located behind the mouth and have fleshy filaments with gill arches and blood vessels which make them bright red-colored.

Water is taken in continuously via the mouth and passed to the gills where the gases are exchanged. Also, the blood capillaries in the gill filaments take up oxygen from the water and give out carbon dioxide.

Fish breathe by opening and closing their mouths. The amount of oxygen dissolved in the water is low, so fish open and close frequently to push water over their gill.

As long as there are adequate amounts of dissolved oxygen in the environment, fish can extract the oxygen needed to function from the water. This is made possible by gills allowing a fish to absorb 85% of oxygen from water.

Bony fishes are one of the few fishes that can breathe without moving. They have the ability to pump water over their gills via muscular action. This requires a lot of energy that the bony fish has to spend to keep their breath.

Fish have evolved a variety of mechanisms for dealing with this challenge. But perhaps the most fascinating adaptations belong to the flying fishes near coral reefs.

Not only do they have increased blood pressure, increased heart rate but larger gills, and they can hold their breath for the longest time which makes it possible for them to fly for a longer duration.

How do gills work?

A fish's ability to obtain oxygen from water is based on a respiratory system composed of a series of highly vascularized internal organs called gills.

The gills work in much the same way as lungs, using a thin membrane called a septum to separate the entrance and exit of blood. Oxygen moves from the environment into the bloodstream through diffusion across this membrane.

For significant gas exchange to take place, there must be a move from one medium to another. Simply put, this is the reason why fish must move to breathe.

Fish gills are composed of filaments, each containing a capillary network that supplies blood cells with oxygen. The flow of water moves past these filaments, which are used to extract oxygen from the water using diffusion.

The gill is made up of many threadlike structures called filaments. The membrane of these filaments is folded into small chambers that are filled with blood, which flows over them via different branching vessels connected to veins.

Oxygen passes out through respiratory surfaces into tiny blood vessels and is transported throughout the body by red blood cells. Once it reaches body tissues it can pass into cell membranes where it enters individual cells for cellular respiration.

In conclusion, fish have evolved a series of complex anatomical and physiological systems to extract oxygen from water, allowing them to maintain an active lifestyle even when they are not moving. We have also learned about how fishes breathe underwater and how their gill works.

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