- 5/19/2025
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TVTranscript
00:00Ours is truly the land of the free and the home of the brave.
00:30A blue planet.
00:35Water covers most of the world's surface.
00:44Here, we are the outsiders.
00:48But under the waves, one group thrives.
01:06Fish.
01:08Fish are masters of the waters.
01:22And sailfish are the fastest of them all.
01:27Their speed makes them one of the ocean's most fearsome predators.
01:31Off the coast of Mexico, 30 sailfish have surrounded a ball of sardines.
01:48To catch their prey requires more than speed alone.
01:51In the tightest turns, fins maintain stability.
02:01Their sickle-shaped tail powers them forwards,
02:04and that extraordinary dorsal fin helps intimidate their prey.
02:08To the naked eye, the action is too fast.
02:21Slowed, their challenge becomes clear.
02:24Just picking a target is hard enough.
02:29Knocking it off balance separates it from the show.
02:35This requires extraordinary skill.
03:06Not every attempt is successful.
03:15But as more sailfish join in, when one misses, another takes its place.
03:30The shoal of sardines is methodically wiped out.
03:36Sailfish are top predators. Very little threatens them.
03:43But for the majority of fish, this is not the case.
03:51For most fish, the open ocean is extremely dangerous.
03:58And some go to extraordinary lengths just to survive.
04:06Flying fish.
04:22Free of the water, they soar on elongated fins, leaving their predators far behind.
04:36A flight of fish.
04:58Escaping predators is not the only test facing the flying fish.
05:05They must also protect their developing young.
05:12These flying fish are searching for the one thing that will make this possible.
05:19In such a vast ocean, it's not easy.
05:26They're in luck. A palm frond.
05:31It's a tiny island, adrift in a huge ocean.
05:38And like an island, it offers shelter not for the flying fish, but for their eggs.
05:48The females lay eggs on the raft, where the males fertilize them.
06:00The first fish spawn, and this triggers the others to start.
06:16Soon, thousands join the melee.
06:23Innumerable strands of eggs are laid.
06:26The raft starts to tilt under their weight.
06:57The best place to lay eggs is right inside the frond.
07:04For some, the attempt proves fatal, and living fish become entombed.
07:19The raft starts to sink under the weight of so many eggs.
07:27But this is far from a disaster.
07:30Sinking away from the surface actually improves the eggs' chances of survival.
07:37In just a few days, having been safely hidden in the depths, they'll hatch out.
07:46Other fish protect their offspring in different ways.
07:50Some go to far greater lengths to care for them.
07:57MUSIC
08:09The shallow waters of southern Australia are home to many strange creatures.
08:26It's a fairytale world of seahorses,
08:34stargazers,
08:39and stingrays.
08:45But none compare with the beauty of the weedy sea dragon.
08:57MUSIC
09:02The dragon's tiny fins beat frantically to prevent the current from sweeping it away.
09:09MUSIC
09:20It's the beginning of spring, the season when sea dragons begin their courtship.
09:27MUSIC
09:35And in the evening light, they start to dance.
09:46MUSIC
09:58In a graceful duet, each partner mirrors the actions of the other.
10:06MUSIC
10:28MUSIC
10:42Darkness will soon draw a veil over the pair, but they will dance on into the night.
10:49MUSIC
10:58MUSIC
11:02Two months later, and the result of their courtship is revealed.
11:15It's the male, and he's the one that's carrying the eggs,
11:19with rows and rows of them embedded in his tail.
11:23MUSIC
11:26That night, the female transferred her eggs to him.
11:30Since then, the male alone has cared for them.
11:35By carrying them with him, he's kept them safe.
11:39MUSIC
11:43MUSIC
11:49And now it's time for his efforts to be rewarded.
11:57The eggs are ready to hatch.
12:00MUSIC
12:03MUSIC
12:11In the calm of a summer morning, a baby sea dragon, with yolk sacs still attached, is born.
12:19MUSIC
12:22MUSIC
12:27The weed bed shelters older dragons that are already able to feed themselves.
12:33MUSIC
12:44Although these dragons were well cared for by their father,
12:47now they must find their own way in the world.
12:52MUSIC
12:55There are fish, however, which provide their young with a safe refuge for far longer.
13:05The South Western Pacific.
13:10A convict fish, and it's something of a marine architect.
13:17Underground, it has created a labyrinth of tunnels.
13:22This adult never ventures out of its burrow.
13:26What it eats is a mystery.
13:34But it doesn't live here alone.
13:38At another entrance, faces peer out.
13:43Juvenile convict fish.
13:47Unlike their parent, the youngsters are not tied to the burrow.
13:55And as they start to emerge, a trickle becomes a flood of fish.
14:08There are thousands of them.
14:13And they all help with the chores.
14:29Many hands make light work.
14:43MUSIC
14:54The young fish swarm together, thousands of mouths gulping plankton.
15:01MUSIC
15:10What the adults eat must somehow involve these youngsters.
15:17Whether the young feed their parents by regurgitating food,
15:21or through some other mechanism, we just don't know.
15:26Whatever the answer, the youngsters provide their parents with a meal,
15:30and in return get a roof over their heads.
15:45Producing young is just one challenge.
15:48Finding food and somewhere to live are further trials fish must face.
15:56The Californian coast. A wide range of species live here.
16:03But all this life means competition for living space is intense.
16:21Old shells are highly prized.
16:26And this one is occupied by a sarcastic fringe head.
16:34These fish are exceptionally quarrelsome.
16:37They have to be to defend their living space.
16:48MUSIC
16:56An octopus.
17:01Inadvertently, it's wandered into the fringe head's territory,
17:05and that can't be tolerated.
17:26The octopus's impressive jab holds the fringe head at bay.
17:40There is more to this behaviour than being bad-tempered.
17:46The fringe head needs to defend its patch if it is to get enough to eat,
17:51and the octopus was competition.
17:56MUSIC
18:04Crabs are not the easiest of mouthfuls.
18:10Because of the shortage of living space, there are constant boundary disputes.
18:16Especially with other fringe heads.
18:20And this one has got too close.
18:26MUSIC
18:29Despite the most extravagant threats,
18:32neither is prepared to back down.
18:37MUSIC
18:55MUSIC
19:03Success, and it's quick to get back to its shell.
19:09A fringe head can never drop its guard. There's too much competition.
19:14MUSIC
19:20Some fish have moved to places where they have fewer rivals.
19:26MUSIC
19:39A mudskipper, a fish that spends most of its life out of the sea.
19:46It can walk on land and breathe air.
19:50Its life is very different from that of most fish.
19:59A fish out of water, maybe, but they thrive here in Japan.
20:09So what's made this upheaval worthwhile?
20:14The answer lies in the mud.
20:19MUSIC
20:22As the tide retreats, it exposes mud flats.
20:27Sunlight hits the rich silt and tiny plants and animals flourish there.
20:34All food for a mudskipper.
20:39But life on land is not without problems.
20:42It's hard work to find a mate.
20:45MUSIC
20:53Jumping high above the mud will get you noticed.
20:58MUSIC
21:15With eyes perched on the top of their heads,
21:18the mudskippers keep a lookout for both friend and foe.
21:24And males fight those who intrude on their territory.
21:29MUSIC
21:46They must also take care not to dry out in the sun.
21:54Rolling in the ooze keeps the skin cool and moist.
22:01For this smaller species, a better option is to retreat underground.
22:08So he digs himself a tunnel down into the mud.
22:25His heap of spoil is an indication of the extent of his excavations.
22:31With the tide flooding the tunnel twice a day,
22:34maintenance is a real burden.
22:41The mudskipper is a real pain in the butt.
22:45He is a man of few words.
22:49He is a man of few words.
22:53He is a man of few words.
22:56He is a real burden.
23:05The tunnel is more than a refuge from the sun.
23:08It serves another very important purpose.
23:12The tunnel is actually U-shaped,
23:15and at the far end is a sealed chamber,
23:18the walls of which are lined with eggs.
23:22The eggs are kept in air as it's richer in oxygen than the water.
23:28The problem is the air that's trapped here won't last for long.
23:33So the male travels to the open end of the tunnel to gulp fresh air.
23:39Back he goes down his tunnel, where he releases it into the egg chamber,
23:45replenishing the oxygen on which the eggs depend.
23:52He will repeat this hundreds and hundreds of times until his young hatch.
24:03This lifestyle is very demanding,
24:06yet the mudskipper has found a way around every problem.
24:11The harsh challenges of life in the ocean
24:14have encouraged other fish to leave the sea.
24:18Not for land, but for fresh water.
24:23Hawaii is the remotest island chain on the planet.
24:29These pools look the perfect place for a fish.
24:33Yet few contain fish, for one very considerable reason.
25:04Surely no fish could swim up this.
25:09But one fish comes from the ocean,
25:12intent on colonising these streams.
25:19It's a tiny goby, and it's a rock climber.
25:25The goby is the largest fish in the world.
25:28It's a tiny goby, and it's a rock climber.
25:36With pelvic fins fused into a disc, which acts like a sucker,
25:40all the goby needs is a film of water to climb through.
25:44The pioneer is soon followed by many others,
25:47possibly following its scent trail.
26:15They clamber on, ever upwards, against the flow.
26:21Drops of water fall like bombs.
26:45False leads waste crucial energy.
26:52Some must rest.
27:02For others, the effort is just too much.
27:08Many die in their attempt to reach the top.
27:14The goby is the largest fish in the world.
27:17It's a tiny goby, and it's a rock climber.
27:41Against all the odds,
27:43a few heroic individuals do make it to the top.
27:51They find themselves in a near-perfect fish habitat.
28:03Where the gobies can feed and grow and breed in peace.
28:09In time, their own young will be swept downstream and out to sea,
28:14and the cycle will begin all over again.
28:32Freshwater presents particular challenges for the goby.
28:38It's a fish.
28:40Nutrients can be in very short supply in spring water,
28:44so here fish must take every chance they can to find food.
28:49The rain that falls on these Kenyan hills percolates through the rocks.
28:55Finally, emerging as crystal-clear pools.
29:00Pools that are home to fish, including barbel.
29:08The fish share these waters with all sorts of creatures.
29:12Including hippopotamus.
29:22These fish are the only ones who can survive in the water.
29:28The fish are the only ones who can survive in the water.
29:35The fish are the only ones who can survive in the water.
29:42These giant vegetarians are no threat to the fish.
29:47In fact, they're key to their survival here.
29:56After a night of grazing on land,
29:59these hippos return to spend the daylight hours in the cooling waters.
30:13And the barbel come to meet them.
30:25Soon, each hippo is trailed by a shoal of fish,
30:29waiting for their breakfast.
30:34Hippo droppings.
30:37Hippo droppings.
30:47But it's not just the hippos' dung the fish are interested in.
30:55When the hippos reach one particular spot in the pool,
30:59they stand still and wait.
31:03And the fish start to clean them.
31:10Removing ticks, parasites and other tasty morsels.
31:17To the fish, the hippos are a mobile cafeteria.
31:26The hippos seem to be enjoying the sensation.
31:33The only thing that interrupts the feast
31:37is the need to take an occasional breath.
31:47Cleaning the hippo's skin was just the hors d'oeuvre.
31:52Now it's time for the main course.
32:03So, in addition to providing skin care,
32:07the fish look after the hippo's dental hygiene.
32:10It's an arrangement that suits both parties.
32:20But perhaps it's the fish that are the overall winners.
32:25For thanks to the hippos,
32:27they are able to feed on the abundant vegetation
32:30that would otherwise be beyond their reach,
32:32growing around their pool on land.
32:39Providing a cleaning service is clearly a good way of getting a meal.
32:45And there is cleaning to be done in the sea as well.
33:01The life of this wrasse
33:03is centred on removing parasites from other reef fish.
33:12Including predatory jacks.
33:21Normally, they would snap up such a little fish,
33:24but this is an established relationship
33:27and both sides know the rules.
33:34With so many jacks and only a few wrasse in attendance,
33:38not all the jacks are going to get cleaned.
33:44But all this life attracts other predators.
33:50Silvertip sharks.
33:58Silvertip sharks.
34:11The reef provides shelter for the smaller fish,
34:14but the jacks remain exposed.
34:18Yet this may be a chance for the jacks to solve their cleaning problem.
34:23They've spotted an opportunity.
34:28Silvertip sharks.
34:42Sharks have skin like sandpaper.
34:47And bumping into the sharks' flanks
34:49helps the jacks to rid themselves of parasites and dead skin.
34:55Perhaps the jacks find this a more effective alternative
34:58to the cleaner fish.
35:01And soon, swarms of jacks pursue the sharks.
35:06All itching to have a scratch.
35:12Unsurprisingly, all this attention bothers the sharks.
35:18And they head back to the blue water.
35:23Leaving the residents of the reef to resume life as normal.
35:36Coral reefs are the richest habitats on Earth.
35:40It's not surprising that with so many different kinds of animals
35:43living so closely together,
35:45some extraordinary relationships have evolved.
35:53A clownfish, a small and defenceless resident of the reef.
36:00It seems to have picked a tough place to live
36:03amongst the tentacles of a sea anemone.
36:08Each tentacle is armed with paralyzing stings that can kill a fish.
36:15Yet the clownfish are totally immune.
36:19For this pair, the anemone is like a castle.
36:24So long as they stay surrounded by the tentacles, they're safe.
36:28And so this is where they choose to lay their eggs.
36:36After carefully selecting the site, work begins on preparing the surface.
36:49Both fish share in the labour,
36:52though it's the larger female who decides when all is ready.
36:59Lines and lines of tiny eggs are stuck to the rock and then fertilised.
37:19They're laid so close to the anemone, they will be safe.
37:25And for the next seven days, they'll receive constant care.
37:31Much of which is provided by the male.
37:36His seemingly obsessive concern for the eggs is for good reason.
37:41His position in the anemone is far from secure.
37:45The female watches his every move.
37:48She's in charge here, and if his efforts don't match up to her standards,
37:52she'll get rid of him.
38:00In line to take over are a host of immature clownfish.
38:08Each waiting to move up the hierarchy.
38:12For the male, the best way to stay in the female's favour
38:16is by lavishing care on the eggs.
38:22So, he focuses all his efforts on keeping them clean and healthy.
38:31The eggs grow up to a height of about two metres.
38:35Clean and healthy.
38:40The eggs grow rapidly, and soon their tiny beating hearts are visible.
38:47It seems he's done a good job.
39:00Clownfish can hide away within an anemone.
39:06But most fish don't have this option.
39:10For some, the only way of avoiding danger is by hiding amongst their own kind.
39:21In shoals.
39:35Packed close together, no one anchovy stands out.
39:42By sensing and reacting to the movements of their immediate neighbours,
39:46thousands can move as one.
39:56For a predator, picking out an individual becomes nearly impossible.
40:05The shoals' unity is its strength.
40:36Yet, each fish is acting from selfish motives.
40:44Moving together, the fish confuse the sea lions so much
40:48that they leave to look elsewhere for a smaller, less tricky encounter.
40:54The sheer size of the shoal defeated the sea lions,
40:57but they're a fish that can overcome such strategies.
41:03Off the coast of South Africa, this huge shoal of sardines
41:07is shadowed by a ragged, dead sea lion.
41:12The sea lions are not afraid of the sea.
41:15They're not afraid of the sea.
41:17They're not afraid of the sea.
41:19This huge shoal of sardines is shadowed by a ragged-tooth shark.
41:30Other sharks join the menacing escort.
41:37The shoal has been driven into the shallows by a cold ocean current.
41:44And this gives the sharks an opportunity.
41:50Hundreds have moved into position.
41:57Sharks have a special sense.
41:59They can detect the electrical signals their prey gives off when it moves.
42:10It's a sixth sense that can give them an edge.
42:14But with hundreds of thousands of fish crammed into the shallows,
42:18the sharks need only rely on their speed and agility.
42:26As the first shark starts to hunt in earnest,
42:29a feeding frenzy breaks out.
42:43The shoal's defences are weakened.
42:45There isn't enough space to manoeuvre.
42:50And the sharks can forge themselves.
42:59Despite the casualties, the shoal is so vast
43:02that the sharks have little effect on its size.
43:14Fish not only come together in great shoals for defence,
43:17but at other critical times in their lives,
43:20when they're ready to spawn.
43:24These events only occur for a few days each year.
43:34Snapper are normally solitary,
43:37but they've travelled here from hundreds of miles away
43:40to gather off the coast of Belize.
43:44Along this one reef,
43:46kubera, dog and mutton snapper form huge shoals.
43:58Sixty metres down, there is an eerie coolness to the scene.
44:05But things are about to hot up.
44:14It's the evening of the full moon.
44:17The tides are just right.
44:26A great column of fish leaves the bottom.
44:30As they rise through the water,
44:32small groups break free of the shoal.
44:44Each burst is led by a female, with the males racing behind.
44:53As she sheds her eggs, they add their sperm to the mix.
45:14By synchronising the time when they gather together,
45:18the maximum numbers of fish can join in this mass spawning.
45:35Millions of fertilised eggs are released,
45:38cast into the ocean currents.
45:44And straight into a dangerous world.
45:54Whale sharks, the largest fish on Earth.
46:06Each shark might weigh ten tonnes,
46:10yet they feed on the tiniest creatures, including snapper eggs.
46:26Life is being created, sustained and destroyed simultaneously
46:32in one huge event.
46:36The struggle for life, encapsulated into a single moment.
46:46The oceans are perilous places to live,
46:49yet fish have developed the most extraordinary means for survival.
46:56Their astounding diversity,
46:58the product of millions of years of evolution,
47:01has enabled them to triumph.
47:06Dominating the one habitat that we have so far,
47:11failed to make our own.
47:36Filming underwater raised all sorts of problems for the life team.
47:43Not least of which was that they were only able to experience the underwater world
47:48for as long as the air on their backs or in their lungs held out.
47:54But over three years, the team were lucky enough
47:57to capture on film some extraordinary moments in the lives of fish.
48:02The waters off the Yucatán Peninsula in Mexico
48:06are a rich hunting ground for sailfish.
48:15Camping in the Yucatán Peninsula
48:18is a great opportunity for the team
48:21to explore the world of fish.
48:25Cameraman Rick Rosenthal has teamed up
48:28with sport fishing captain Anthony Mandillo
48:31to try and film the hunting behaviour of these amazing animals.
48:35It's fish!
48:38Feeding birds lead them to the sailfish.
48:41Right here.
48:43Getting to the bait balls and into the water quickly is key
48:46before the feast is consumed.
48:49Get ready.
48:52They're going to eat it.
48:54Everybody hang on.
48:59Let's go swimming now.
49:05It's all very well telling Rick to hurry.
49:08But these fish are capable of swimming at over 60 miles an hour.
49:12And they're not afraid of water.
49:15But these fish are capable of swimming at over 60 miles an hour.
49:20Just keeping up with them is hard enough.
49:24Come on.
49:42Getting right in amongst the action is vital
49:45but Rick has to try to avoid becoming part of it.
49:49Bills nearly one metre long,
49:52scything through the water at breakneck speed
49:55are guaranteed to get the heart racing.
50:07But Rick holds his nerve
50:09as the sailfish pick off sardine after sardine
50:12right in front of him.
50:19Almost as soon as it started,
50:22it was all over.
50:28That's a wild sea show out there today.
50:31Really wild.
50:33Must have been 50 sailfish if there was...
50:36or 49.
50:38But very aggressive fish, very hungry,
50:40everybody on the move.
50:42And I had to just keep kicking and kicking and kicking
50:45and I had to just keep kicking and kicking and kicking
50:48and kicking and kicking and keeping the action.
50:51After a while, the sardine patch was eaten up to just a little sliver.
50:55And then it was over.
50:58Nearly 2,000 miles away on the other side of the Caribbean,
51:02another crew is taking a slightly different approach.
51:05They are trying to film flying fish.
51:11The team sets out at dawn on the hog snapper,
51:14a commercial fishing boat.
51:16Conditions are in stark contrast
51:19to the gleaming sport fishing boat in Mexico.
51:24It's Doug. He's ready for action. Look.
51:34They are hoping to use the local fishermen's expertise
51:38to put them in the right place at the right time.
51:44So you catching this food?
51:46You catching dinner, lunch and breakfast in now?
51:49Roger.
51:51It's not a big boat and the crew's bedroom has now become the kitchen.
51:55We are having fried bacon, fried egg this morning.
51:58Fried bacon, fried eggs.
52:02I'm the trainee, sir,
52:04so I don't get to wear the white wellies.
52:07LAUGHTER
52:11Rather than racing around the ocean chasing the action,
52:15the flying fish team have to sit it out
52:18and wait for the fish to come to them.
52:22Flying fish will spawn onto debris in the water
52:25and the team tie on to a floating palm frond
52:28to try and make sure they're close by in case the action begins.
52:33And sure enough, they don't have long to wait.
52:38THEY CHATTER
52:49Thousands of fish have massed below the surface,
52:52all intent on reaching the frond.
53:01And the frond is not the only thing that they're trying to lay their eggs on.
53:07MUSIC PLAYS
53:29The weight of the eggs sinks the palm frond
53:32and puts an end to the spawning and to the crew's filming.
53:37MUSIC FADES
53:50At moments like that, we did the job for...
53:53Everything was right.
53:55The light was right, blue water,
53:58the four tonnes of flying fish all going mental.
54:02Thanks, Barry. You're welcome.
54:04But now the fish's attention has turned to something bigger.
54:08They're spawning directly onto the boat.
54:12Barry is worried as he drags up a huge sheet of eggs.
54:15Want to bring it in the boat and check it out?
54:17I cleaned this off, like, five minutes ago, right?
54:21Right now the problem is there are too many flying fish around us.
54:26If we go through the night with the lights on and stuff,
54:29more and more and more will keep coming.
54:32What they're doing here is they're actually laying on the boat now.
54:35So the boat has become their object, and that is not good.
54:38So basically you're worried that if we just stay on this drift,
54:41we're going to sink the boat?
54:43Five hours from now, that will be 3,000 pounds.
54:46Yeah.
54:47In the back here, they will sink the boat.
54:49OK, so we've got to leave this thing.
54:51Yeah, we can't stay here.
54:53Just five minutes of spawning has produced this.
54:58The team have no option but to move on.
55:03The next day, the search for flying fish begins all over again.
55:07This time, the team want to film the fish doing what they're famous for.
55:12We've got some lovely shots of them spawning,
55:14but now the really hard bit of trying to get them flying.
55:17It's going to be a good challenge.
55:22The fish are around, but they're all too far off to film.
55:29The action is impressive this morning.
55:32Unpredictable, but impressive, but it's distant,
55:35and it's not happening next to the boat today.
55:37They're either being chased off by something, or they're just not interested.
55:40Look, look, look!
55:42Ah, it's alive!
55:44Ay-yi-yi.
55:47The next day, the crew decides to try a different approach.
55:53All right, let's go!
55:59Now they're just where they need to be,
56:01but it puts them directly in the firing line.
56:06I guess that's what.
56:15Despite being bombarded,
56:17their strategy seems to be working.
56:20Despite being bombarded, their strategy is paying off.
56:24That was amazing.
56:26We spent a long time in that wee boat today.
56:28Thanks.
56:29But the last two hours were just off the scale.
56:32We were just getting shot after shot.
56:34We need...
56:35Can't wait to watch in the big monitor, but it felt really good.
56:40And Doug is right.
56:42It worked.
56:44Flying fish taking to the air and flying.
56:48Slowed down 40 times.
57:12By working with people more used to catching fish than filming them,
57:16the life team have been able to gain a unique insight
57:20into the hidden world of fish.
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