The number one requirement for a fish is obviously water. Every fish needs water to stay alive. This is because, just like all living organisms, they require oxygen to stay alive, and they are designed to get this from water.
The only reason why they do not stay on land soaking up oxygen from the air like you and me is that they possess gills instead of lungs which helps them convert and absorb the dissolved oxygen present in water.
However, there are such wide variants of fish species, with varying anatomy and special features that allow some of them to get oxygen from the air as well as the water, and also swim.
Every seasoned fish keeper or aquarist knows that some fishes are in fact mammals, and they do have lungs or other physical features that help them get all the oxygen they require to stay alive and even store them for some time as they swim underwater.
How Long Can a Fish Stay out of Water? Despite the dependability of fishes on water, some fishes are known to be able to stay out of water for some length of time. Depending on the type of fish, some can stay for just a few seconds while some can stay for several days, and even months out of water.
Different Fishes Breathe in Varying Water Conditions
The fact is that different species of fish can survive in several water conditions. Some fishes actually cannot survive without coming to the surface often to take in air, such as the whale.
Species of mammal fishes such as this include; the bottlenose dolphin, blue whale, minke whale, beluga whale, Some fishes even live in small puddles or muddy swamps and are not required to stay in flowing water, which is contrary to popular opinion.
It might seem astounding to consider, but there are actually a lot of fishes that can stay out of water for an amazingly long time.
Can a fish survive out of water?
Although most fishes do not have the right anatomy to extract oxygen directly from the air, many are still able to survive for some bit of time. While you may wonder if your aquarium fish can live without water, the best environment for them to survive naturally is in water.
When taken out of their natural habitat where they are suited to extract oxygen, fishes start to suffocate and soon die. Ultimately, a fish cannot survive forever out of water. It is only a matter of time before it begins to lose itself and suffocate.
If you have an aquarium or a fish tank, you shouldn’t make the mistake of intentionally emptying all the water from the tank based on the assumption that fishes can survive without water.
While your pet fish might survive out of water for about 10 minutes, it is an unideal and cruel thing to subject your fish to.
Those few minutes your fish spends outside water would really stress it out as a result of the gills flapping and trying to extract oxygen from the wrong environment.
What happens to fish out of water?
The average fish put out of water is usually very uncomfortable. It has no access to oxygen and soon begins to suffocate and gasp for air. It is not unusual to see a fish flap its fins and attempt to find water by all means. The gills then arch and the fish collapses from the effort of trying to ‘breathe’.
A fish that becomes this frantic immediately when it is out of the water shows that it has no supplementary organ or lungs to help it survive for long out of water.
However, this doesn’t happen to a lot of fishes, as many of them are suited to breathing out of water for an impressive and almost unbelievable amount of time. Some of these types of fishes are listed below;
What fish can breathe out of water?
Some fish are more adapted to staying out of water for some time, while some die very quickly when taken out of water. Some fishes are known to seek air by coming out of the surface often to breathe. However, it is a known fact that they have to return back to the water. Some fishes have an amphibious nature, that is, they can breathe in water and on land.
One of such fishes is the Mudskipper. This is a very interesting and amazing thing to note. Mudskippers are known to be able to live most of their life on land, even though they are a specie of fish. This is because the skin of the mudskipper is peculiarly designed to absorb oxygen easily into its bloodstream. It has its blood vessels close to the skin surface and does very fine in a muddy or swampy location for as long as they want to.
Similar to this fish is the Rockskipper fish or the coral blenny. This is a freshwater fish that can skip around from place to place, find new water habitats, and even find mates for themselves while on land. As long as it is moist and can find food, the Rockskipper is known to be able to stay several hours on land.
One other kind of fish that can breathe out of water is the Walking Catfish. Imagine a fish that shuffles or ‘walks’ when it finds itself on land. That seems quite freakish, but it is exactly what the Walking Catfish is known to do.
You find them after they probably get washed up from the water by heavy rain or tide. They propel themselves forward with their pectoral fins and breathe in the air using separate organ asides their gills, and they can survive a good amount of time before they get back into the water.
Catfish generally have strong adaptability to different water conditions. A number of catfish, probably being kept alive for sale, can be put in a large bowl or tank with just a little water to keep them wet. They can stay alive in this condition for several hours (up to 15-18 hours)
The Snakehead fish is also known to be able to last a very long for up to six days out of the water and sometimes even for months! It is a freshwater fish and can travel on land to find a new habitat when it isn’t surviving well in its previous habitat.
Thus, if you have this kind of fish in your aquarium, you should be cautious about putting it out of water for some time, so it doesn’t start to scuttle away, as it can be quite harmful to an unsuspecting victim.
The Lungfish is also, like its name implies, breathes with its lungs and can survive a very long time outside water.
Eels are also very commonly seen on land, slithering both on sandy or rocky surfaces, even though they are classified as fishes. A lot of fishes are very resilient and hardy, and some like the climbing perch have the bizarre and incredible ability to breathe outside water, as it has a combination of gills and lungs.
The Mangroove rivulus is also known to be adapted to live both in and out of the water, with their skins that can function just like gills in required situations.
The Killfish is also famous for its ability to shuffle on land for a good length of time. They do this purposefully in order to get themselves back into water.
Other fishes such as species of whales and dolphins which are mammals get all the required air from the atmosphere directly and not from water. They do not have gills but possess some sort of airbags along with their bodies.
Therefore you see them dive out of the water in a seemingly happy display. Essentially, this is to breathe in air and store them for use along with their airbags for some amount of time under the water, before they are required to get back to the surface to breathe again.
Why does a fish die when removed from water?
Fish die when out of the water as a result of suffocation. Just the way you can’t stay alive when you have no access to air. Fishes get their oxygen when their gills dissolve them from the water and then absorb this into their bloodstream.
If a fish depends only on its gills for breathing, then it would not be able to get oxygen from the air the way humans do with their lungs.
It is simply the way a human who breathes with his lungs underwater would soon suffocate and drown. Many fishes do not last more than a few seconds or minutes at best before they begin to die.
However, some fish might not die immediately when it is removed from the water. This can be as a result of it still being wet or in a watery surrounding even when it is not in water.
As long as there’s still some bit of water on the gills of the fish, it can make use of the dissolved oxygen to breathe for some time. Fishes like catfish can stay up to 15 hours when removed from the water.
Although, it is a fact that fishes sometimes move out of a water habitat when it’s no longer suitable or healthy for them. Sometimes, the oxygen level in the water is so low, such that the fishes that require a high amount of oxygen find it difficult to survive.
They thus have the capacity to leave such water conditions and source for something else. Some leave their water habitats due to threat from predators.
Also, since fish are not terribly bright creatures, they might mistakenly swim or get washed to the land, or even jump out by themselves. Some are suited to survive under such circumstances while some are not.
The important thing to know is that the average fish would soon start to show signs of exhaustion before one hour when there’s no water flowing through their gills. They then have to flap helplessly and frantically all the while.
How long can you keep fish out of water?
Keeping a fish just for the sake of it might not be the nicest way to treat your pet or aquarium fishes. This is because it is torture to stay without access to oxygen for an extended period. However, if for some reason you have to do so, or if it happens by mistake, then it would be necessary to know how long you can keep your fish out of water.
It is very possible for your pet goldfish to mistakenly jump out of its bowl and stay on the floor for some length of time alive, but gasping.
So in order to determine how long you can keep your fish out of the water, you must bear in mind the specie of fish you have, as well as your purpose for keeping it.
In addition, fishes go through a process known as estivation to stay without water for a long period of time. This is done whereby they wrap themselves in a natural sort of cocoon and dig themselves into the mud and stay in a dormant state for a pretty long time, sometimes up to a year.
This is usually done during the dry season when the water dries up in the wild, and they can’t get the required oxygen. A fish being kept out of water gets tired and would thus need to adapt through some other means, hence the process of estivation.
Finally, we can see that the rules regarding fishes being in the water at all times have a lot of exceptions, such as we have highlighted here.
Some fishes are clearly amphibious fishes, while some are full air-breathing fishes. However, note that your aquarium fishes would always need water to survive, and a very good amount of it if they must thrive in your aquarium.
However, you should be aware that different species of fish are adapted to various conditions, and some might actually require oxygen beyond what is available in the water.