We’ve all heard and probably used the expression “fish out of water”, but how long can a fish really live out of water. As an animal that gets their oxygen from the water, most species are unable to breathe through the air. They cannot survive for long outside water.
Are you planning to start your fishkeeping journey? Whether you are a beginner or experienced hobbyist, everyone will wonder about this question at some point. How long is it okay for you to leave your fish out of water before it dies? After all, you do need to move them from one aquarium to another.
There is no universal answer, as it all depends on the species and type of fish. Some fish can actually survive for a surprisingly long time outside the water. Today, let’s explore this further and find out how long your little friend can live out of its natural habitat!
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Can a Fish Survive Out of Water?
The short answer: yes, but only temporarily. A fish needs oxygen to survive and most species breathe through their gills, which allows them to take oxygen from the water. Some types of fish can also absorb oxygen through their skin.
In general, no fish can breathe when they are on land. If you leave them out there for too long, they will become dry and suffocate. This also does not mean a fish taken out of the water will immediately die. Some of them, especially those that can tolerate low-oxygen conditions, can stay alive for longer periods of time. Another factor includes the situation that the fish is in.
Let’s say that a fish accidentally jumps out of their tank and hits a ceramic surface. There is a puddle of water around it. This means it can still breathe by absorbing the oxygen in that water. As long as the gills are moist and there is enough oxygen content, it may be able to survive for a longer while.
Moreover, there are six species of fish with the unique ability to breathe in the air, such as the lungfish. In addition to gills, they also have special organs that function like the primitive lungs of most amphibians.
But assuming that you’re asking this question for your pet at home, then your fish cannot survive out of water. So, the best thing to do? If you really have to take them out to move them elsewhere, just do it as quickly as you can.
How Long Can a Fish Live Out of Water?
When it comes to aquarium fish, the hardiest species can live up to 10 minutes out of water. Then again, the exact number depends on their size, type, and environment.
Common freshwater species like goldfish are weaker than their saltwater compatriots. It is because they typically have smaller bodies and more frail gills. They can die after just three minutes of the gills not moving.
Some species of catfish, such as channel and blue catfish, are especially strong. They can survive in waters with low oxygen, and some people claim that these fishes can survive for several hours out of water. Trout, on the other hand, is much less tough.
Additionally, fish that live in colder temperature have slower metabolisms, which means they might survive longer if the environment is also cool. This is because their lower metabolic rates allow them to use up oxygen at a slower rate. Likewise, fish that live in warm climates need much more oxygen to survive and will die faster out of water.
Which Fish Can Survive the Longest Out of Water?
As we have mentioned, each species of fish is different from the other. They have varying body compositions, metabolic rates, and characteristics. Some fish can live longer out of water than others, while some will die within seconds or even minutes.
But whether you are fishing or changing your pet’s water, try not to deprive a fish from water for too long. This will only cause them unnecessary suffering! With that said, which fish can live the longest outside of water?
Most people wouldn’t believe that the mangrove rivulus can survive for two months, or around 66 days, out of water. However, they can indeed! This is because the fish can extract oxygen from the air, thanks to their special skin. They are also categorized as amphibious fish.
Another type of fish is the West African lungfish. Although they cannot necessarily survive land much like the mangrove rivulus, this lungfish can wrap themselves in a cocoon and burrow deep in mud. Then, they will go on a dormant and breathe through their primitive lungs.
Finally, you may have also heard of certain species of catfish that can “walk” on land. Their fins can be used to crawl or wriggle on dry land, while their special organ lets them breathe from the air.
How Long Can Fish Survive without Oxygen?
We have talked about how and how long a fish can survive without water. But what about oxygen?
After all, the only reason a fish needs to be in water in the first place is because they can only take oxygen through water, and not air. So, what happens when they are underwater but there is hardly any oxygen?
While there are no obvious symptoms of low oxygen, you can generally tell when the level drops too low in an aquarium. Your fish will become more lethargic and weaker, eating less, and moving less. Their gills will open and close rapidly as they try to get more oxygen from the water.
At worst, the fish will be reaching towards the surface where the water holds more oxygen. In most cases, you should not be worrying about low oxygen, especially if the tank is well-kept and not overcrowded.
Yet some unique species like goldfish and crucian carp can last up to five months without taking in oxygen! How? They can produce enzymes that transform carbohydrates anaerobically into alcohol, which can then exit the body through their gills.
At the end of the day, whatever species of fish we are talking about, they do need water to survive. After all, they are aquatic animals that live in the water.
The next time you are changing the water in your fish tank, you know now how long they are likely to survive out of water. Recap: not long at all!