If you’ve ever wondered how those aquatic creatures can stay underwater for extended periods, you likely want to know – how long can fish actually hold their breath? As an air-breathing species, the idea of being submerged for more than a few minutes makes us humans feel uneasy.
However, fish have specially adapted over millions of years to thrive in water environments where oxygen can be scarce. Keep reading to uncover the fascinating respiratory systems that allow fish to hold their breath for hours, days, or even months at a time.
If you’re short on time, here’s a quick answer to your question: most fish can hold their breath anywhere from a few minutes to several days depending on the species. Fish like bettas and goldfish can survive for 5-10 minutes without oxygen, while larger tuna and sharks have special adaptations to stay underwater for hours.
Respiratory Systems of Fish
Gills
Fish respiration primarily relies on the gills, which are specialized organs that allow gas exchange with water. Gills are composed of filaments containing a dense network of blood vessels. As water passes over the gills, dissolved oxygen moves into the bloodstream while carbon dioxide exits.
This countercurrent exchange maximizes the diffusion of gases.
The gills of fish are incredibly efficient at extracting oxygen from water. Some fish are capable of extracting over 80% of available oxygen. The structure and high surface area of the gills allow for rapid gas diffusion.
Additionally, fish can increase ventilation and blood flow through the gills to boost oxygen uptake when needed.
Accessory Breathing Organs
While most fish depend entirely on their gills, some species have evolved accessory breathing organs that enable them to obtain oxygen from air.
Lungfish have a primitive lung connected to their throat that allows them to breathe air. Many lungfish can sufficiently meet their oxygen needs with gills alone but will gulp air from the surface to supplement breathing. This adaptation enables lungfish to survive out of water for extended periods.
Some fish also have specialized swim bladders that facilitate breathing. The swim bladder normally helps fish maintain buoyancy, but in some species it also functions as a primitive lung. The African sharp-toothed catfish and several species of gouramis possess this dual-purpose swim bladder.
Cutaneous Respiration
Though relatively limited, fish can engage in cutaneous gas exchange across their skin and fins. While only a small fraction of required oxygen is obtained this way, it can help supplement gill breathing.
Species with extensive vascularization in the skin and fins, such as eels, rely more heavily on cutaneous respiration.
The contribution of cutaneous respiration increases in hypoxic conditions when the oxygen level in water is very low. During environmental hypoxia, vasodilation in the skin maximizes surface area for gas diffusion.
Certain species of catfish and carp substantially boost cutaneous respiration to overcome poor water quality.
How Long Different Fish Can Hold Their Breath
Betta Fish and Goldfish
Betta fish and goldfish, two common freshwater fish kept as pets, can hold their breath for quite a while. Bettas can survive out of water from 30 minutes to an hour, thanks to their special organ that allows them to breathe oxygen from the air.
Goldfish, on the other hand, have been known to survive without water for hours.
Both species have this ability thanks to their adaptation to living in puddles and ponds that can dry up in their native habitats. The next time you clean your betta or goldfish tank, make sure to work fast so they don’t have to hold their breath too long!
Carp
Members of the carp family, like common carp and crucian carp, have an astounding ability to live outside water for multiple days at a time. They can breathe air using special air sacs that work like lungs. Carp will gulp air at the water’s surface when pools start drying up.
This gives them plenty of oxygen to stay out of water for up to 5 days. They can also swim long distances between vanishing pools in search of a more permanent home. So if you see a dead carp on land, don’t rush to throw it back in the water just yet!
Tuna
As extremely fast, powerful swimmers, tunas are able to circulate oxygen better than other fish. Their ability to hold their breath far surpasses a human’s. In experiments, yellowfin tuna held their breath from 40 minutes to over 2 hours before showing any signs of distress.
Their high volume of myoglobin (oxygen-binding protein in muscles) may contribute to this incredible ability. So while you may be out of breath after a tough workout set, a tuna is ready to keep trucking for miles and miles!
Sharks and Rays
| Species | Breath Holding Time |
|---|---|
| Great white shark | Over 40 minutes |
| Tiger shark | Over 1 hour |
| Whale shark | Potentially hours – still unknown |
| Manta ray | At least 20 minutes |
Of all fish, sharks and rays are likely the supreme champions when it comes to holding their breath. Some species can go over an hour without taking in new oxygen.
For example, great white sharks can hold their breath for more than 40 minutes. They can travel long distances, breach the water’s surface, and drag their prey down – all on a single breath. The largest shark, the filter-feeding whale shark, can likely last for hours thanks to its slow metabolism.
So next time you try holding your breath, remember there’s a shark out there that could outlast you by a landslide!
Extreme Examples
Lungfish
Lungfish are able to survive out of water for extended periods thanks to their remarkably evolved lungs. Studies have shown the Australian lungfish can remain in oxygen-poor mud for up to four years, slowing its metabolism and breathing through a small opening to take in air.
Truly astounding, these primeval creatures enter a state of torpor to hold their breath for more than three times longer than the maximum recorded time a human has held their breath (24 minutes). Using a complex system of adaptations, lungfish can hibernate through drought and be ready to swim away when the water returns.
Desert Pupfish
An extremely hardy fish, the desert pupfish has adapted to survive in hot, oxygen-starved pools in North American deserts. Capable of breathing air directly from the water’s surface, it can withstand water temperatures over 104°F and oxygen levels as low as 0.1 ppm (compared to average levels of 8 ppm).
Desert pupfish can even survive for up to 16 hours out of water by lying dormant in moist soil. Truly a survivor in extreme environments, this small fish shows incredible abilities to hold its breath through adaptations over eons.
Its amazing durability continues to fascinate biologists studying the limits fish can withstand.
Why Do Fish Need To Hold Their Breath?
Fish need to hold their breath because they use oxygen in water to breathe through their gills, unlike land animals that breathe air. When water passes over the gills, blood vessels in the gills extract oxygen from the water and transfer it to blood.
If there is not enough oxygen in the water, fish may suffocate. This is why they need to move to areas with sufficiently oxygenated water regularly.
Most fish have either lungs or a specialized organ called a labyrinth organ that allows them to breathe air directly. This supplements the oxygen they get from their gills. It enables them to survive out of water or in water that has low oxygen, for limited periods.
Some fish like bettas and snakeheads can breathe air through their mouths and survive for days out of water.
The length of time fish can hold their breath depends on the species. For instance, tuna and sharks are ram ventilators – they have to keep swimming forward to force water through their gills to breathe. So they can only hold their breath when stationary for minutes at a time.
Species like lungfish and bettas though have adaptations that allow them to hold their breath for hours.
When underwater oxygen levels deplete due to factors like excess pollution or algal blooms, fish will initially accumulate closer to the surface before dying en masse if the condition persists. This allows them intermittent access to oxygenated surface water.
Having the ability to hold their breath even for a while helps them tide over such periods of poor oxygenation.
So in essence, fish hold their breath to oxygenate tissues despite not technically breathing air. The length they can go without breathing depends on special adaptations like supplementary breathing organs. And breath holding even temporarily helps them respond to scenarios of oxygen lack in water.
Understanding the breath holding capacity of different fish species can actually help assess water body health during environmental surveys. It also helps the aquarium hobby understand species specific needs.
Conclusion
As we’ve explored, fish have evolved a diverse array of respiratory strategies over millions of years to be able to hold their breath anywhere from minutes to months. While small fish like bettas can only survive without oxygen for 5-10 minutes, larger predatory fish have specially adapted blood and muscles that enable them to be active hunters underwater for hours at a time.
And in extreme cases, certain fish take breath-holding to the next level – lungfish can estivate for years, and desert pupfish have evolved to withstand near-anoxic swamp waters. Understanding the breathing capacities of fish sheds light on just how well adapted they are to their aquatic worlds where oxygen fluctuates dramatically.
Whether only needing a quick gulp at the surface, or having multi-day oxygen stores, fish have developed the ultimate tricks for life underwater.
