Pratique du Shadowing: Do Fish Need Water… When They're Already In It? - Apprendre l'anglais à l'oral avec la vidéo

Fish spend their entire lives surrounded by water, so it seems like a strange question to ask.

Do fish actually get thirsty?

Humans and other land animals feel thirst when the body needs more water.

But what about creatures that are literally swimming in it all day?

Do they ever experience that same urge?

And if they're already surrounded by water, how would they even drink?

As it turns out, the answer is more interesting than a simple yes or no.

Different kinds of fish deal with water in very different ways, and some actually have to drink constantly just to survive.

So let's dive beneath the surface and find out how fish manage their water balance right here, on History of Simple Things.

Humans experience thirst because our bodies are constantly losing water through sweat, breathing, and other processes.

When our fluid levels drop, the brain signals us to drink.

Fish don't experience thirst exactly the way humans do.

Scientists believe they don't have the same conscious sensation that makes us think, I need a glass of water.

Instead, their bodies automatically regulate water and salt levels through biological processes.

In other words, fish don't necessarily feel thirsty the way we do,

but they still need to maintain the proper amount of water inside their bodies.

How they accomplish this depends largely on where they live.

Freshwater fish live in rivers, lakes, and ponds where the surrounding water contains very little salt.

Interestingly, the fluids inside their bodies are saltier than the water around them.

Because of this difference, water naturally moves into the fish through their skin and gills through a process called osmosis.

It's almost like their bodies are constantly soaking up water.

That means freshwater fish have the opposite problem humans have.

Instead of worrying about dehydration, they have to prevent themselves from becoming too diluted.

As a result, freshwater fish rarely drink water.

They simply absorb enough through their bodies and then remove excess water by producing large amounts of dilute urine.

Their kidneys work continuously to keep everything balanced.

So if you have goldfish in an aquarium, those fish aren't swimming around taking little sips of water.

Most of the water they need is already entering their bodies naturally.

Life in the ocean presents a completely different problem.

Seawater contains far more salt than the fluids inside a fish's body.

Because of this, water tends to leave the fish through osmosis.

In a sense, saltwater fish are constantly losing water to the environment around them.

To compensate, they actually drink seawater, sometimes quite a lot of it.

Of course, drinking salty water would be disastrous for humans.

The excess salt would only make us more dehydrated.

But marine fish have evolved special systems that allow them to handle this challenge.

After swallowing seawater, their digestive systems absorb the water they need.

The extra salt is then removed by specialized cells in their gills and by their kidneys.

So yes, many saltwater fish do drink water regularly.

If they stopped, they would gradually lose too much water and become dehydrated.

Sharks are fish too, but they have developed a different strategy.

Instead of constantly drinking seawater, sharks maintain unusually high concentrations of chemicals such as urea in their bodies.

This makes the fluids inside them nearly as concentrated as the seawater outside.

Because the balance is much closer, sharks lose less water through osmosis than many bony fish do.

species still take in water, but they don't depend on drinking seawater as heavily.

It's one of many adaptations that have helped sharks survive for hundreds of millions of years.

The secret behind all these differences is a process called osmosis.

Osmosis occurs when When water naturally moves from an area with lower concentrations of dissolved substances to one with higher concentrations,

the movement continues until balance is reached.

For freshwater fish, water flows inward because their bodies are saltier than their surroundings.

For saltwater fish, water tends to flow outward because the ocean is saltier than they are.

This invisible movement of water determines whether fish need to drink or avoid drinking altogether.

Without these mechanisms, fish would quickly lose the balance necessary to survive. Can fish become dehydrated?

Surprisingly, yes.

Marine fish can become dehydrated if they cannot replace the water they lose.

Changes in salinity, disease, or damage to their gills can interfere with their ability to maintain proper water levels.

Fish kept in aquariums can also experience stress if the water chemistry is incorrect.

Salt levels that are too high or too low can upset the delicate balance their bodies depend on.

Even migrating species like salmon face unique challenges.

Salmon are born in freshwater, spend much of their adult lives in the ocean, and later return to freshwater to spawn.

As they move between these environments, their bodies undergo remarkable changes to adjust from one water-balancing strategy to another.

It's almost like switching between two entirely different operating systems.

So, do fish get thirsty?

The answer is both yes and no. Fish probably don't experience thirst in the same way humans do,

but maintaining water balance is just as important for them.

Freshwater fish generally don't need to drink because water constantly enters their bodies

while many saltwater fish actually drink seawater to replace the water they lose.

The next time you see fish swimming peacefully in an aquarium or the ocean, remember that their bodies are constantly performing an incredible balancing act.

Even in a world made entirely of water, staying hydrated isn't as simple as it seems.

Thank you for joining us on this journey through the history of simple things.

Don't forget to like, subscribe, and stay tuned for more stories woven through the smallest details.

Qu'est-ce que la technique du Shadowing ?

Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.

Pratique du Shadowing: Do Fish Need Water… When They're Already In It? - Apprendre l'anglais à l'oral avec la vidéo

About This Lesson

Key Vocabulary & Phrases

Practice Tips

Qu'est-ce que la technique du Shadowing ?