The Tiny Fish That Climbs a 50-Foot Waterfall
Summary
Deep in the Congo, a fish smaller than a french fry climbs a roaring 50-foot waterfall using secret hooks on its fins — and it takes ten whole hours. Scientists finally filmed the whole adventure, and what they saw changed how we think about fish.
Transcript
0:00The Climbing Fish
There is a fish in Africa that goes rock climbing. Not swimming. Not jumping. Climbing — straight up a wall of roaring water taller than a five-story building. And here is the part that makes scientists' jaws drop: this fish is smaller than a french fry. You could line up ten of them across your hand. It has no arms. No legs. No fingers. No rope, no helmet, no sticky spider feet. And yet it spends ten whole hours creeping up a fifty-foot waterfall while thousands of gallons of water try to push it back down. For years, people who lived near the Congo River noticed something strange. There were fish swimming happily in calm pools way, way above the falls. Nobody could explain how they got up there. Then a team of scientists hauled cameras into the jungle, sat in the cold mist, and finally caught the whole thing on video for the very first time. What they filmed was so surprising they had to replay it in slow motion just to believe their own eyes. Ready to meet the tiniest mountain climber on the planet?
0:59Meet The Shellear
So let's meet our hero. This little fish is called a shellear. Say it with me: SHELL-eer. Silly name, right? It sounds like something you would find on a beach. Shellears live in the rivers and streams of Africa, and most of them are about as long as your pinky finger. Some grow a bit bigger, but honestly, if one swam past you in a stream, you might think it was a leaf. They are slim and smooth, sort of shaped like a tiny torpedo, with a soft silvery-brown color that blends right into the sand and pebbles. Here is your first wow fact of the day: shellears are cousins of some of the oldest fish families still swimming around today. Their family tree goes back an enormous amount of time. So while they may look plain and ordinary, they are actually little living pieces of ancient history. And this ordinary-looking fish is about to do something no ordinary fish should be able to do. Because hidden on its body is a secret tool. Want to guess what it is?
1:52The Mighty Congo
Before we get to the secret, you need to picture where this happens. Grab a globe in your mind and spin it to Africa. Right in the middle sits an enormous river called the Congo. It is one of the mightiest rivers on the whole planet, and here is a fact that might make your brain wobble: in some places, the Congo River is deeper than a football field is long. There are spots so deep and so dark that scientists still find fish nobody has ever named. The river winds through a steamy green rainforest full of monkeys chattering in the treetops, butterflies the size of your palm, and trees so tall they block out the sky. Rain falls almost every day, which keeps the rivers full and rushing. Now, all that water has to travel downhill toward the sea. And when a river goes downhill fast, you get rapids, tumbling white water, and — you guessed it — waterfalls. Big ones. Loud ones. The kind you can hear before you can see. And one of those waterfalls is exactly where our story gets wild.
2:49Wall Of Water
Now imagine standing at the bottom of this waterfall. First thing you notice is the noise. It is not a gentle trickle. It is a constant roar, like a hundred washing machines all running at once. You would have to shout to talk to the person next to you. Second thing: the mist. Water smashes into the rocks so hard that it explodes into a cloud of tiny droplets, and that cloud floats everywhere. Your hair gets damp. Your glasses fog up. Everything is slippery. Now look up. Way up. The wall of rock in front of you rises about fifty feet, which is roughly as tall as a five-story building, or about eight grown-ups standing on each other's shoulders. Water pours down it nonstop, day and night, year after year. The rock is black and glossy and covered in slick green algae. Here is the wow fact: a waterfall like this pushes so much water that it could fill a swimming pool in seconds. And a fish the size of a french fry looks at that and thinks: I've got this.
3:42The Big Mystery
Here comes the mystery that started everything. Above that waterfall, up in the calm streams at the top, people kept finding shellear fish. Lots of them. Happy, healthy, swimming around like they had always lived there. And everybody scratched their heads, because there is no fish elevator. There is no back staircase. The only way in from below is straight up that thundering wall. So how did they get there? For a long time, people came up with guesses. Maybe birds accidentally carried them? Maybe floods washed them upward somehow? Maybe there was a hidden underground tunnel? Every guess had a problem. Birds do sometimes move fish eggs, but not this many fish, this often. Floods push water down, not up. And nobody ever found a tunnel. The answer sat there for years like an unopened present. And the funniest part? The truth was even stranger than any of the guesses. Because the fish were not being carried, or washed, or teleported. They were doing it themselves — with a move nobody had ever recorded. So a team of scientists decided to find out.
4:42Scientists Arrive
Picture the scientists arriving. They are not wearing lab coats — that would be silly in a rainforest. They are in boots and quick-dry clothes, carrying waterproof backpacks stuffed with cameras, notebooks, and snacks. Getting there is an adventure all by itself. Long drives on bumpy roads. Boat rides. Then hiking through thick, buggy jungle where every leaf drips on your head. When they finally reach the falls, they have to set up cameras on slippery rocks without dropping anything into the churning water below. Now here is a real challenge nobody thinks about: keeping a camera lens clear when you are standing inside a permanent cloud of mist. Scientists wipe those lenses over and over and over. Some of them use little cloths tucked in their sleeves, like a magician's trick. They also work in shifts, watching for hours, because nobody knows exactly when the fish will show up. That is the not-so-glamorous secret of science: a whole lot of waiting. But when the waiting finally paid off, what appeared on that rock face was absolutely astonishing.
5:42Caught On Camera
There it was. On the wet black rock, just to the side of the crashing main flow, a tiny silver shape was moving. Upward. The scientists leaned in. It was a shellear, no bigger than a french fry, and it was not swimming. It was not being splashed around. It was pressed flat against the stone, wriggling, gripping, and steadily climbing. Then they spotted another. And another. Soon they realized the rock face had dozens of little climbers spread across it, all working their way toward the top like the world's smallest rock-climbing team. The fish moved in a stop-and-go rhythm: a burst of wiggles, then a pause, then another burst. Sometimes one would slip a little and immediately catch itself. Here is your wow fact: the scientists watched some of these fish climb for around ten hours straight. Ten hours! That is longer than a whole school day, plus lunch, plus recess, plus homework. And the biggest question was still hanging in the air: what on earth was keeping them stuck to that rock?
6:38The Secret Hooks
Time for the secret. When scientists looked at these fish under a microscope, they found something incredible on their fins and along parts of their bodies: hundreds of teeny-tiny hooks. They are so small you cannot see them with just your eyes. Zoomed way in, they look like a field of miniature spikes or a row of little sharp bumps, almost like the roughest sandpaper you have ever touched — except arranged in neat patterns. Scientists call these little structures odontodes. That is a big word, so here is a fun way to remember it: odont means tooth. So odontodes are basically tiny tooth-like bumps. Yes — this fish has miniature teeth on its fins. And here is the truly amazing bit: these little hooks are not just for show. They catch on every rough spot, every bump, every microscopic dent in the rock. Where you and I would see one smooth slippery surface, the fish's hooks find a whole mountain range of grips. So how does a fish actually use hundreds of hooks to move upward? That is where it gets clever.
7:37Grip And Wiggle
Let's break down the climbing move, because it is genuinely brilliant. The fish presses its body flat against the wet rock. Then it pushes its fins outward and down, digging those tiny hooks into the stone. Grip. Then it curves its body into an S shape and wiggles, pulling itself up just a tiny bit. Then it grips again with the hooks in the new spot. Grip, wiggle, grip, wiggle. It is a lot like how you would climb a rope in gym class: hold on, pull up, hold on again, pull up again. Except imagine doing it with a fire hose spraying you in the face the entire time. Here is a wow fact for you: each little upward move might only be about as long as a grain of rice. So to travel fifty feet, this fish has to repeat that grip-and-wiggle motion thousands and thousands of times. It is the ultimate never-give-up move. But hold on — if water is pouring down that rock, why doesn't it just blast the fish off? The answer is a sneaky trick of physics.
8:31The Slow Lane
Here is one of the coolest science ideas in this whole video, and it is called the boundary layer. Try this in your imagination. When water flows over a surface, the water in the middle rushes fast. But the water touching the rock — the very thinnest layer, right against the stone — moves much, much slower. It is like traffic on a highway. Cars in the middle lanes zoom. Cars squeezed against the edge crawl. That slow, thin sheet of water hugging the rock is the boundary layer, and it is the fish's secret hallway. Because the shellear is so small and so flat against the stone, it can tuck itself inside that calm little zone while the wild water roars past just above it. Being tiny is not a weakness here. It is a superpower. A big fish would stick out into the fast water and get swept away instantly. Our little french-fry-sized hero fits perfectly in the safe lane. And now you understand something most grown-ups do not know. So what does the actual climb look like, hour by hour?
9:26Ten Hour Journey
Let's follow one shellear on its big day. Hour one: it leaves the calm pool at the bottom, finds a wet patch of rock at the edge of the falls, and pushes out of the water. Its hooks catch. Up it goes. Hour two and three: steady progress along the wet stone, slipping into little grooves and cracks where the water is calmer. Hour four: it hits a smooth section with almost nothing to grab. It pauses. It shifts sideways to find a rougher route. Smart! Hour five and six: past the halfway point now, with mist swirling all around. Hour seven: another rest, tucked into a shallow dip. Hour eight and nine: the last long push. Hour ten: it slides over the lip at the top into calm, quiet water. Done. Here is the wow fact: relative to its body size, that climb is like a person climbing something taller than the tallest skyscraper on Earth — using only their fingertips. And nobody handed this fish a map or a training plan. So how does it survive that long out of the water?
10:23Breathing While Climbing
Great question, and here is the answer: the fish is never really out of water. Remember that thin sheet flowing down the rock? The shellear stays inside it the whole time, like a swimmer staying under a very shallow blanket of water. Its gills stay wet, so it keeps breathing. Gills, by the way, are the amazing feathery parts on the side of a fish's head that pull oxygen straight out of the water. Think of them as underwater lungs. As long as they stay damp, the fish is fine. And the mist helps too. That permanent cloud around a waterfall keeps everything soaked, so even a fish resting on a rock stays comfortably wet. Here is the wow fact: some fish around the world can breathe a little through their skin when it is wet, and moist skin is a real advantage for anything doing this kind of journey. So our climber is basically wearing its own portable puddle. Clever, right? But now for the biggest question of all. Why would any fish choose to do this? What is up there that is worth ten hours of climbing?
11:18The Secret Playground
Imagine you found a playground that nobody else knew about. No lines for the slide. All the swings free. Snacks everywhere. That is roughly what the top of the waterfall is for a shellear. Down at the bottom of the river, life is crowded. Lots of fish, lots of competition, everybody nibbling the same food. But the streams above the falls are quiet, calm, and much less busy, because almost nothing else can get up there. There is soft algae growing on the rocks, tiny water bugs drifting by, and plenty of space to grow up. It is a peaceful little neighborhood in the sky. Here is the wow fact: scientists think this is why the climbing behavior developed in the first place. Over an enormous stretch of time, the fish that were slightly better at gripping wet rock reached those quiet upper streams, thrived there, and passed their gripping gear on to their young. Little by little, the hooks got better, and the climbers got braver. Which brings us to a sweet part of the story: what happens to the baby fish?
12:15Full Circle Journey
Here is where the story loops around like a giant circle. Fish that live above the waterfall lay their eggs up there in the calm water. When those eggs hatch, the babies are unbelievably small — some baby fish start life smaller than a grain of rice. And the current gently carries many of them downstream. Which means, yes, over the falls. Down they tumble, into the churning water at the bottom, and off into the big river. There they grow up, eating and getting stronger, until one day something inside them says: it's time. And then they turn around and climb back up the wall their parents came from. A whole round trip. Down as a baby, up as a climber. Here is the wow fact: many animals make round-trip journeys like this, and scientists call it migration. Salmon do it. Sea turtles do it. Some butterflies do it across entire countries. But almost none of them do the last part by rock climbing. And speaking of other animals — you are not going to believe who else climbs waterfalls.
13:12Hawaii's Suction Fish
Fly with me across the ocean to Hawaii. In the streams there lives a little fish called a goby, and it has a trick that is somehow even wilder. The goby has a suction cup on its belly. An actual built-in suction cup, made from two of its fins fused together, exactly like the ones you stick on a bathroom mirror. And it uses that suction cup to inch up waterfalls that can be hundreds of feet tall. One kind of Hawaiian goby has a second suction area near its mouth, so it climbs by alternating: mouth sticks, belly slides up, belly sticks, mouth slides up. Scientists have nicknamed this the inchworm climb, because it scoots exactly like an inchworm crawling along a twig. Here is the wow fact: some of these gobies climb cliffs so tall that if you scaled it up to human size, it would be like you climbing a mountain in one go without stopping. Nature basically invented the suction cup long before humans did. But suction cups and hooks are not the only tools out there.
14:10Salmon Jump Instead
Now let's talk about the most famous waterfall athletes on Earth: salmon. You have probably seen the videos. Big silver fish flinging themselves out of the water and flying through the air to get over a ledge. Salmon swim all the way from the ocean back to the exact stream where they hatched, sometimes traveling hundreds of miles upriver. And when they meet a waterfall, they do not climb. They jump. Here is the wow fact: a strong salmon can launch itself higher than most kids can jump, straight up out of the water, using a powerful flick of its tail against a swirling pool. Scientists discovered that clever salmon use the churning water at the base of a falls almost like a trampoline, riding the upward push to gain extra height. So now you know two totally different strategies for the same problem. Salmon say: go big, jump it. Shellears say: go small, climb it. Both work. Both are amazing. And there is a third strategy that happens in complete darkness, deep underground.
15:07The Walking Fish
In the caves of Thailand lives a fish so unusual that when scientists first described it, other scientists asked them to double-check. It is called the cave angelfish, and it lives its whole life in pitch-black underground rivers. It has almost no eyes, because in total darkness eyes are not much use. It is pale, small, and easy to overlook. But here is the astonishing part: this fish walks. Not wiggles. Not slides. Walks. Its fins connect to its body in a way that lets it move with a stepping motion, and researchers who studied it said the way it moves is surprisingly similar to how four-legged animals walk on land. It uses that walking motion to travel up rushing waterfalls inside the caves. Here is the wow fact: studying this fish helps scientists imagine how, an incredibly long time ago, some of the very first animals might have started moving from water onto land. A tiny blind fish in a dark cave is helping us understand one of the biggest stories in nature. And there are still more climbers to meet.
16:08Catfish Climbers
Meet the suckermouth catfish. If anyone in your family has a fish tank, you might have one right now — they are the flat, armored-looking fish that stick to the glass and slowly graze around like little vacuum cleaners. In the wild, in South America, these catfish climb rocks in fast rivers using a mouth that works like a super-strong sucker plus rough skin covered in — guess what — odontodes. The same tiny tooth-bumps our shellear has! Isn't that wild? Two totally different fish, living on two different continents, thousands of miles apart, both invented the same tool. Scientists have a name for this: convergent evolution. It means nature bumped into the same great solution twice, in two separate places. It is a bit like two kids in different countries both inventing the same board game without ever meeting. Here is the wow fact: sticky, gripping, hooked surfaces show up all over the natural world — on geckos, on burrs that stick to your socks, on catfish, on shellears. Nature loves a good grip. But how does gripping actually work? Let's zoom way, way in.
17:13Zooming Way In
Time for a science zoom-in. Take a rock that looks perfectly smooth. Run your finger across it. Feels flat, right? Now imagine shrinking down until you are smaller than a speck of dust. Suddenly that smooth rock looks like a wild landscape of hills, valleys, cliffs, and canyons. Nothing is truly smooth when you get close enough. Even a mirror has a bumpy surface at the tiniest scale. That is exactly what the shellear's hooks are for. Each little odontode is like a miniature climbing hand, reaching into those microscopic canyons and hooking on. Multiply that by hundreds of hooks across the fins, and suddenly a fish that weighs less than a paperclip can hold on against rushing water. Here is the wow fact: this is the same reason your shoes have grippy patterns on the bottom, and why rock climbers use special sticky rubber shoes. More texture equals more grip. So next time you look at the bottom of your sneaker, remember: you are wearing the same idea a tiny African fish figured out first. And there is a second helper working too.
18:16Sticky Water Science
The second helper is something you have already played with without realizing it: the stickiness of water itself. Have you ever pressed two wet glasses together and found they were surprisingly hard to pull apart? Or noticed a wet piece of paper clinging to a table? Water molecules like to hold hands with each other and with surfaces around them. Scientists call it surface tension and adhesion, but you can just think of it as water being a little bit sticky. For a very small, very light creature, that stickiness matters a lot. It helps hold the shellear against the stone, working together with its hooks. Here is the wow fact: this same water stickiness is why some insects can walk straight across the top of a pond without sinking. Their weight is so small that the surface of the water acts like a stretchy trampoline. Being small changes the rules of the world in the most delightful ways. Our tiny climber lives in a version of physics that would never work for you or me. And that leads to a question scientists really wanted to answer.
19:15Science Tools
The question was: how do we study something so tiny doing something so fast, in a place so wet? Scientists got creative. First, super slow motion cameras. A normal video records around thirty pictures every second. A high-speed camera can record hundreds or even thousands. When you play that back slowly, a wiggle that lasted a blink stretches out into a long, clear movement you can actually study. Second, waterproof action cameras strapped right onto the rocks, filming for hours while the researchers stayed dry-ish nearby. Third, microscopes back at the lab to count and photograph the hooks. Fourth, careful notes: how fast, how far, what time of year, how many fish. Here is the wow fact: sometimes the most important science tool is not fancy at all. It is patience. Some of these researchers sat beside that waterfall for days before seeing what they came for. If you have ever waited quietly to spot a bird or a squirrel, congratulations — you already have the number one skill of a field scientist. And this discovery almost did not happen at all.
20:20Hidden In Plain Sight
Why did it take so long for anyone to film this? A few reasons, and they are all pretty relatable. Reason one: the waterfall is hard to reach. It is deep in the rainforest, far from roads, in a place where hiking with heavy gear is genuinely exhausting. Reason two: the fish are tiny and camouflaged. A brown-silver fish on wet dark rock is basically invisible from a distance. Reason three, and this is the big one — nobody was looking. If you have never heard of a climbing fish, you do not stand at a waterfall staring at the rocks hoping to see one. You look at the water. Here is the wow fact: scientists estimate that a huge number of species on Earth have never been described or studied. Not thousands — likely millions. There are creatures out there right now doing amazing things that no human has ever seen. Some of them might live in the stream near your town. That is not a sad thought. That is the most exciting thought in the world. Because it means discovery is not finished. Not even close.
21:18Robots Copy Fish
Now here is something you might not expect: engineers absolutely love this fish. When people build machines that need to climb, they run into the exact same problems the shellear solved. How do you hold onto a wet, uneven wall? How do you stay stuck without slipping, and then let go when you want to move? So engineers study climbers in nature — geckos, insects, suction-cup fish, hooked-fin fish — and borrow the ideas. There is even a name for this: biomimicry, which just means copying nature's designs. Here is the wow fact: teams around the world have already built small climbing robots inspired by gecko feet and hooked animal grips, using tiny spines that catch on rough walls exactly like odontodes catch on rock. Those robots could one day inspect the outside of tall buildings, check bridges for cracks, or explore places that are tricky for people to reach safely. All from watching animals do what they already do. Nature has been running the world's longest science experiment, and we get to read the results. So what do we still not know?
22:19Questions Remain
Here is the honest truth, and I love telling kids this part: scientists still have loads of questions about these climbing fish. How do the fish know when it is time to climb? Is it the season? The temperature? Something in the water? Nobody is certain. Do they all climb at the same time of day, or spread out? Do some of them try, give up, and come back later? How many make it to the top out of every hundred that start? Do the hooks wear down and grow back, like how some animals replace their teeth? Are there other waterfalls, in other parts of Africa, with climbing fish nobody has filmed yet? Almost certainly yes. Here is the wow fact: in science, a good discovery does not close a door. It opens ten new ones. Every answer creates fresh questions, which is exactly why scientists never get bored. And the person who answers one of those questions in twenty years? Could genuinely be someone watching this video right now. But before we finish, let's talk about the biggest lesson this fish teaches.
23:15Small And Steady
Think about what this fish is up against. It weighs less than a paperclip. It is facing a fifty-foot wall of thundering water. Every single upward move gains it about a grain of rice worth of progress. It slips sometimes. It has to stop and rest. And it keeps going for ten hours. Nothing about that is fast. Nothing about that is flashy. It is just tiny effort, repeated an enormous number of times, until an impossible-looking thing becomes done. That is honestly one of the best lessons in all of nature. Learning to read? Grain of rice at a time. Getting good at drawing, or soccer, or the piano? Grain of rice at a time. Nobody climbs a waterfall in one jump. Here is the wow fact to hold onto: the shellear is not the strongest fish in its river, not the biggest, not the fastest. It just does not stop. And that turned out to be the winning strategy. Small and steady beat big and strong. Now, let's zoom out and look at the amazing place all this happens in.
24:13Waterfall Neighborhood
A waterfall is not just water falling. It is an entire neighborhood. That constant mist creates a special zone where plants grow that could not survive anywhere else nearby — soft green mosses, delicate ferns, and slick films of algae that coat the stones. Those algae are food. Tiny water bugs come to munch them. Bigger creatures come to munch the bugs. Frogs love the damp. Birds swoop through the spray. Dragonflies zip past like little helicopters. And because water crashing down traps air inside it, the pool at the bottom of a waterfall is usually extra full of oxygen, which fish love. Here is the wow fact: waterfalls also act like natural gates. Because most animals cannot get past them, the creatures living above and below can end up quite different from each other over long stretches of time. It is like two separate worlds with one loud doorway between them. And our little shellear is one of the very few travellers with a key to that door. Let's put the whole adventure together one more time.
25:13The Whole Journey
Let's do a quick replay of the whole journey. Our shellear starts in the big warm river at the bottom, no bigger than a french fry. It swims to the base of a roaring fifty-foot waterfall. It finds a wet patch of rock at the edge of the crash zone and pushes itself out of the deep water and into the thin sheet flowing over the stone. Its hundreds of microscopic hooks bite into the rock. Grip, wiggle, grip, wiggle. It stays inside the slow boundary layer where the water is calm, hidden right beneath the roaring rush. Its gills stay wet in the mist so it keeps breathing. Hour after hour it climbs, resting in grooves, choosing rougher routes, catching itself when it slips. Ten hours later, it slides over the top into a peaceful stream almost nobody else can reach. And here is the wow fact to top it off: it does all of that without a single lesson, map, or coach. It just knows. Pretty incredible for a fish you could balance on two fingers, right?
26:08Be Curious
Now let's talk about you for a second, because everything in this video started with somebody being curious. Somebody noticed fish where fish should not be. Somebody asked a question that sounded a little silly. Somebody was willing to sit in cold mist for days to find out. You can do the exact same thing without going anywhere near a waterfall. Next time you are at a park, sit still for two minutes and just watch one ant. Where is it going? Does it follow the same path as the other ants? Watch a bird land — which foot touches first? Look at a puddle after rain and see what floats and what sinks. Here is the wow fact: some real scientific discoveries have come from ordinary people noticing something odd in their own backyard and telling a scientist about it. Curiosity is not a special power that only certain people get. It is just paying attention on purpose. And attention is completely free. Speaking of things you can try, I have got a fun little experiment for you.
27:01Try This At Home
Here is your safe at-home challenge, and it takes about one minute. Grab a plate or a smooth plastic lid and a small cup of water. Put one drop of water on the plate. Now slowly tilt the plate. Watch closely. See how the drop clings for a moment before it finally slides? That clinging is the same water stickiness that helps our shellear hold on. Now try it again, but this time put the drop on something rough — like a paper towel or a piece of cardboard. What happens? It grabs on much better, doesn't it? Rough surfaces plus sticky water equals grip. You just demonstrated the shellear's superpower on your kitchen table. Bonus round: put a drop of water on a coin and see how many more drops you can add before it spills. Most people are amazed at how tall that little dome of water gets. Ask a grown-up to help with the cleanup, and remember: this experiment stays at the table, not near real waterfalls. Now, one last thought before we say goodbye.
27:54Recap And Goodbye
Let's lock in the coolest things you learned today. One: there is a fish called a shellear, smaller than a french fry, that climbs a fifty-foot waterfall in the Congo. Two: it grips using odontodes — hundreds of microscopic tooth-like hooks on its fins. Three: it hides inside the boundary layer, the slow thin sheet of water hugging the rock, which is why being tiny is an advantage. Four: the climb takes around ten hours, longer than a school day. Five: it climbs to reach quiet upper streams with less competition and plenty of food. Six: other climbers exist too — suction-cup gobies in Hawaii, walking cave fish in Thailand, and armored catfish in South America. And seven: engineers copy these tricks to build climbing robots. Not bad for one video! Here is my favorite part of all of this. The world is absolutely stuffed with astonishing things that nobody has filmed yet. Somewhere right now, something incredible is happening with no audience at all. So keep looking. Keep asking. Tell someone in your family the fish-that-climbs-waterfalls fact tonight and watch their face. Stay curious out there — I'll see you next time.
More videos
Series: science (English)