Hi. My name is Remik and I'm a biologist from the Gdynia Aquarium.
Today I will tell you a little bit about seahorses.
I think everyone knows what a seahorse looks like, and the Gdynia Aquarium has it in its logo,
but what really distinguishes these animals from other creatures
that we can encounter on the coral reef or in the aquarium?
Seahorses belong to the Syngnathidae family.
They live in areas providing a large number of shelters, such as seagrasses, coral reefs, or mangrove forests.
Depending on the species, they reach from 1.5 to 35 cm in length.
Their name refers to the chess piece, the knight, whose head resembles a seahorse's head.
Although they are fish, their body is devoid of scales, and their skin is stretched over bony plates.
Seahorses swim in a vertical position,
using their dorsal fin, which can move up to 35 times per second.
This is a feature that sets them apart from other fish.
Their pectoral fins, located on both sides of the head behind the eyes,
are used for steering.
They also lack a tail fin, as they have a prehensile tail.
They differ from other fish not only in their body shape but also in their way of life.
The most unusual differences occur in their mating behavior.
During copulation, the male receives a packet of eggs from the female,
which he then places in his brood pouch located on his belly.
A pair of seahorses can court each other for several days.
During this time, they can change colors, swim together while holding onto their tails,
or even hold onto the same blade of grass with their tails.
Then the ultimate dance begins,
during which the male, by pumping water through his brood pouch, shows the female that it is empty.
When the female's eggs mature, she and her partner let go of everything they held onto,
and then drift upwards with their heads pointed towards each other.
In the final moment, the lid on the male's brood pouch opens for about 6 seconds,
during which the female, using an organ called an ovipositor,
lays anywhere from a few to several thousand eggs into the pouch depending on the species.
Then they both return to the safe and intricate seafloor.
The fertilized eggs then settle into the wall of the male's brood pouch
and are surrounded by sponge-like tissue.
The pouch acts as an incubator and maintains the eggs in the proper conditions.
The young hatch inside the pouch, where regulated salinity prepares them for life in the sea.
Throughout the gestation period, which lasts from two to four weeks for most species,
the female visits her male every morning.
When the brood is ready to be born, the male pushes them out of the brood pouch using muscle contractions.
They usually give birth at night and are ready for another batch of eggs in the morning when their partner returns.
Seahorses do not take care of their young after birth.
The fry are susceptible to predators or ocean currents that can wash them away from their feeding grounds
or into areas where temperature can damage the tiny seahorse bodies.
Less than 0.5% of young ones survive to adulthood, which explains why litters are so large.
Although it is not known whether seahorses mate for life,
it is known that they bond for at least one breeding season.
As you can expect, keeping seahorses in aquariums is no easy feat.
Firstly, the water must meet specific parameters.
Above all, it must be crystal clear.
Seahorses can't be denied charm and grace, but they certainly won't be Olympic swimmers.
The water in their tanks can't be strongly agitated,
as seahorses simply wouldn't be able to overcome such strong wave movements.
For the same reason, feeding can also be problematic.
Seahorses are unable to chase their prey throughout the entire tank.
That's why zooplankton and small crustaceans
like copepods, young shrimp, or artemia are used as food.
Despite this, they have to eat practically all the time due to the lack of a stomach.
They often anchor themselves in one spot and wait for food to appear in front of their mouths.
That's why it's important to have plenty of small, non-escaping and accessible food swimming in the aquarium for them.
Other species swimming in the tank with them can't be too greedy or aggressive either.
Firstly, because seahorses simply won't be able to defend themselves against their attacks,
but also because they can starve the seahorses by eating all the available food.
Keeping adult seahorses is difficult enough, but breeding them is a real art.
Now that you know how clumsily adult seahorses feed,
think about the difficulties their 5-millimeter babies have with eating.
This is one of the most challenging moments in breeding.
Providing the right amount of food adapted to the small seahorses is crucial.
This food can be copepods or brine shrimp, but only if they are still very young.
The artemia larvae that we want to feed the small seahorses cannot be older than 3 hours.
After this time, they may be too big, and their shells too hard to digest.
This scheme is additionally complicated by the fact that the artemia hatching time ranges from 18 to 28 hours.
Depending on their geographic origin.
This means that we need to estimate the birth time of seahorses
24 hours before they hatch, with an accuracy of up to 60 minutes.
One hour late or early, and the young seahorses won't have anything to eat.
That's why at our aquarium, we feed young seahorses with copepods,
which do not have a size problem.
Sometimes, the young seahorses need to be separated from the rest of the tank's inhabitants,
but they cannot be taken out of the water under any circumstances.
Even a momentary contact with air can cause the seahorse to inhale a bubble of air,
which will prevent the young seahorse from diving again.
As you can see, many elements of breeding success depend on perfect time management,
often down to the hour and minute.
But as befits such extraordinary animals, their breeding method is equally extraordinary.