Ondina and Erik swimming

Merpeople are human/fish-hybrids, the legends of which go back more than three thousand years. They're magical creatures of the seas, and the basis for the hit television shows H2O: Just Add Water and Mako: Island of Secrets. According to Sirena, "real" merpeople are born naturally in the sea.

Moon Pool

Main article: Moon Pool

The Moon Pool is a pool of water connected to the ocean that can turn regular humans into merpeople when the full moon passes over the cone of the dormant volcano. It is located on Mako Island off of The Gold Coast in Australia. The second Moon Pool is in a Sea Cave in Ireland. The Moon Pools are known to have turned Cleo Sertori, Emma GilbertRikki Chadwick, Isabella Hartley, Gracie, Louise ChathamJulia, EvaCharlotte Watsford, and Evie McLaren into mermaids, and broke a tail-less spell on Zac Blakely.

On special occasions, the Moon Pool reacts to the Full Moon magically and unleashes special effects, such as taking away a merperson's powers, either temporarily or forever, or enhancing a merperson's powers.


Mermaid Sketch

Mermaid Sketch from Mako: Island of Secrets MEDIA KIT

Merman Sketch

Merman Sketch from Mako: Island of Secrets MEDIA KIT

All merpeople share the same basic traits:

When mermaids come into contact with water for ten seconds, they grow a long golden-orange-copper tail and a matching top. Their tails are covered in scales and end in a classic dolphin-shaped fluke. They also have a short dorsal fin running along the backs of their tails from their waists to a little more than halfway down the tail.

When mermen come into contact with water for ten seconds, they grow a long ocean-blue tail that ends in a pointy-shaped fluke. They also have a short dorsal fin running along the backs of their tails from their waists to a little more than halfway down the tail.

A merperson's tail is also very strong, this is shown when Emma saves Zane Bennett by smashing in the steel door on Miss Chatham's boat, or when Nixie breaks the frozen surface of the pool in the underwater entrance to the Grotto. Merpeople also lose their clothes they're wearing in human form which only reappear when they become human again. Their hair keeps it's natural length, but any hair-ties, headbands, hair clips or hairspray disappears, along with their clothes. When they dry, their hair returns to whatever hairdo it was in. Moon Rings accompany the merperson's transformation, i.e, if they have a human form and transform, the Moon Ring is still there and vice versa, indicating that the ring is a magical object.

The transformation also occurs when merpeople are exposed to snow or ice, but since Southern merpeople never interact with snow, they will also develop Snow Rash and become feverish. Just a only drop can change them. The only way to cure them is by applying dried seahorse powder onto their skin. Northern, Western, and Eastern merpeople are immune to Snow Rash. Northern merpeople born and raised in icy waters presumably are resistant to the cold.

Invisible merpeople can be detected with thermal imaging technology.

It is still unknown how born mermaids reproduce, since mermen haven't been seen for thousands of years by the mermaids, due to the mermen living on land after the great war that happened between them. While merpeople appear mostly mammalian in nature, young mermaids are often called hatchlings, implying that born mermaids lay eggs like fish and turtles. It is possible that mermen have children with humans. If this is true, the genes of merpeople must be very strong for Erik to have been born with powers.

The differences between mermaids and mermen suggests that the two creatures may be a bit more distant than the men and women of the human race or are a separate subspecies, but they are close enough to be considered two sides of the same species.


Although considered as the same creature, mermaids and mermen have different behaviors. Mermaids are determined to learn more about their powers and master to control them, instead of gaining more. They even have Mermaid School, which teaches their young how to use their powers and using them wisely to guard the sea and the Moon Pool. They live in pods and are never alone, and aren't really as solitary as mermen (although Lyla is considered a loner, but isn't that solitary and cooperates with the other two). Mermaids usually travel with or hang around in groups of at least two or three other mermaids.

Mermen, on the other hand, are brought up and raised on land. Most likely to hide from the mermaids after losing the war to them, which explains why mermaids mentioned that mermen haven't been seen for a while. Originally, both mermaids and mermen lived in groups or pods, but after the great war that happened between mermaids and mermen, mermen no longer lived in pods in the sea. They are described as solitary and territorial. They are also described as power-hungry by the mermaids, and would do anything to obtain power. Zac does not really have this typical mermen behavior, but upon seeing the Trident for the first time, he becomes obsessed with obtaining it. He also believes that he is destined to possess it after he falls into a moon spell but then snaps right out of it the moment he touches the Trident for the first time. Unfortunately, after being betrayed by the mermaids, Zac comes to see them as corrupt, trouble-making, selfish, devious, and power hungry. He doubles his efforts to get the Trident and denounces the mermaids as his enemies, vowing to claim vengeance on them for all the trouble they caused him. Later, as the mermaids make many unsuccessful attempts to strip Zac of the Trident, he even goes so far as to try take Mako from the mermaids after he mistakenly believes that they are calling in reinforcements to attack him for the Trident. All of this causes Zac to inadvertently recreate the war between mermaids and mermen and nearly finish the job the mermen of the past began.

Merpeople fear humans as they believe land people will hunt them if they discover they exist. Many mermaid laws forbid ever going near land people or their homes and mermaids who married humans were banished from the pod. The relationship between mermaids and humans was much worse hundreds of years ago. Ancient mermaids would use their siren songs to enchant humans and lure them to a watery grave to preserve the mermaids' secrets. They may have also used storms to sink ships who spotted them or wandered to near the pod's home. Such methods are now forbidden. Mermaids also had an ancient game similar to tug-of-war. A mermaid must use whatever power she has to drive a ship to her side. Ancient mermaids may have used real ships long ago but like the siren songs, using real ships was probably forbidden. In "Battlelines", when Rita asked what to do if a mermaid's invisibility fails to hide her from humans, Nixie replies that they "drown them," reinforcing the fact that mermaids may not care about humans. However, this view is not shared by all mermaids and some may be fascinated by the land and its people. Mermaids will also help humans like summoning gusts of wind for stranded sailors and will even fall in love with humans like Sirena, Mimmi and Rita.

Both mermaids and mermen live on a diet of seafood. They will eat any kind of seafood, such as crabs, lobsters, prawns, tuna, and salmon no matter how it is cooked. In fact, natural merpeople don't like to eat land foods, such as pancakes, instead finding crustaceans, fish, and seafood more appealing to their tastes.

Born mermaids are very naïve about the human world, human terminology, and human technology when they first come to land. This causes them to sometimes stand out in the crowd and draw attention to themselves. When they first get legs, they have difficulty walking but get used to it after lots of practice. Mermaids are also instinctively terrified of cats. However, they can learn to cope with this fear and conquer this fear like Rita who loves her own feline, Poseidon. Sirena also shows affection to Rita's beloved pet but her friends, Ondina and Nixie, though they no longer fear cats, they continue to dislike Poseidon.

On their birthdays, mermaids give gifts rather than receive them. Mermaids lack any form of currency and they do not build dwellings. Instead they sleep under the stars. How mermaids raise their hatchlings is a complete mystery. Mimmi was raised by her mother until the latter's disappearance. Aquata and Sirena are sisters but never mentioned anything about other family members like a mother while Ondina, Nixie and Lyla have never mentioned anything about blood relatives. To mermaids, the pod is family and they take it upon themselves to raise young mermaids, even if they do not share any biological relations. Pods will even accept and raise mermaids from other pods like Mimmi.

According to Ondina, mermaids share the secret that binds them together, and that mermaids who are in the same pod felt like sisters towards one another. This statement was confirmed as Nixie and Lyla stated that Sirena was like a sister to them. This method also had convinced Rikki to give Weilan and Ondina the Jiao Long Bracelet.


Main article: Pods
Mako Mermaid Pod

Mako Pod

As revealed in Mako: Island of Secrets, there are pods of natural-born mermaids all around the world. The Mako Pod consists of over a hundred. When the moon is full, natural mermaids all around the world honor the moon with a ceremony. Natural-born mermaids live on a seafood diet and wear seashells and similar items as jewelry. According to Mimmi and Ondina, the Northern Pod knows the best spells and potions. The Mermaid Council, with Veridia as head of the Council, make the laws and rules for the Mako pod to follow.

Some of these are:

  • It is forbidden to sing the Enchantment Song.
  • It is forbidden to associate with land people and it is especially forbidden to use a Moon Ring to go onto land.
  • It is forbidden to let land people into the Moon Pool, especially during a Full Moon.
  • It is forbidden to fall in love with a land person.
  • It is forbidden to travel too close to land.
  • It is forbidden to reveal your powers to humans.

Mermaids of the pods use the Full Moon as a source of magic and power. They create Moon Rings out of blue moonstone and use them to accomplish many feats and spells, as the rings can heal injuries but can also cause destruction.

Young mermaids, also known as hatchlings, in their respective pods must go through training to be worthy of these rings. Mermaid School teaches them to use their powers correctly and to be sensible in the difficult choices made through mermaid life.


Ancient mermaids used to sing their respective Enchantment Songs or create storms to kill land people who came too close to them.

Eons ago, a pod/army of mermen carried the Trident in battle and behaved in a destructive manner until mermaids from each of the 5 oceans defeated them by drawing on the powers of the oceans and locked the trident away in the Trident Cave with one of the kinder mermen's help.

The Chinese Mermaid was a member of the Eastern pod and fell in love with a land boy. Another Eastern pod heard of this and punished the mermaid and the pod by casting a spell to turn the land boy into a Water Dragon.

Mermen are brought up on land in foster families, go to land school and mingle with humans. Mermen do not have moon rings. Mermen no longer have pods since the war between mermen and mermaids.

Aurora threatened the Northern Pod and later redirected her threat to the Eastern Pod. Nerissa came to help them and fought alongside them for years. Nerissa went to face Aurora and was never seen or heard from again. During the battle, Aurora turned Nerissa into the Water Dragon and made her attack the Eastern pod, destroying the Eastern pod. The survivors were forced to flee to the land of China, and eventually the pod split. Having lost all sense of herself, Nerissa was sent to destroy the entire Eastern Pod while she was the dragon. After the Eastern Pod was destroyed, she was put in a deep sleep and Nerissa was believed to be dead by her fellow mermaids.

Mermaid Council

Mermaid Council

A pod consisting of over a hundred mermaids took refuge on the reef of Mako Island. When Sirena, Lyla and Nixie are charged with guarding the Moon Pool during the full moon ceremony, a boy named Zac Blakely fell into the pool by accident and became a merman. When the pod found out what happened, they blamed the girls for breaking the rule and cast them out while the rest of the pod fled to the South Pacific where they joined another pod. To correct the problem, the girls broke the rule of using a Moon Ring to go on land, and later the one that forbade singing the Enchantment Song. They then encountered Rita Santos, a mermaid of the pod who had long since found new life on land, and asked her to complete their training. In the end, Rita deemed them worthy of having Moon Rings.

Rita teaching the girls how to create a storm

Rita teaching the girls

With Zac Blakely being a merman, after he returns the Trident to the chamber he becomes a temporary member of the little pod formed by Sirena, Nixie, and Lyla. While Rita doesn't share their adventures, she is considered part of their pod due to her involvement with the girls in guidance and training. Sirena, Mimmi, Ondina, Evie, and Zac form a little pod in Season 2. Erik, being a merman, becomes a temporary member of the little pod formed by Mimmi, Ondina, Evie, and Zac.

A Canadian Mermaid was caught on a footage singing the Northern Pod Enchantment Song.

Powers and Abilities


Main article: Merpeople Powers

Mimmi, Ondina, and Weilan using their powers

It is possible that the place where the merperson's transformation happened affects the powers over water, e.g. the Moon Pool at Mako Island gave the people the power to control, freeze and boil water, but the pool in the Sea Caves of Ireland where Bella changed gave her the power to turn water into a jelly-like substance and to turn water into a substance similar to crystal or glass.

Natural Merpeople Abilities

These are natural abilities that all merpeople are shown to have, which stem from their own physiology and are not magical in nature.

  • Underwater Breathing - Merpeople can stay submerged for long periods of time but they still need to breathe air. Merpeople can hold their breath for at least 12 hours before needing to resurface but with more practice merpeople can stay under for much longer. When mermaids remain breathless, they do not die, unlike humans. They "sleep" underwater, and just awaken when they breathe air again. They can only hold their breath in mer-form. When merpeople are infected with Fish Fever, they undergo changes and develop gills. It is possible that during this time, they can actually breathe underwater.
  • Limited Transformation - When a merperson is completely dry, their tails transform into human legs. Just a one drop can change them into their mer-forms. Ten seconds after touching water, they will revert back to their true forms. A long orange-copper tail with a matching top for mermaids and a long ocean-blue tail in place of their legs for mermen. All clothing, including tops, accessories and watches are absorbed by the merperson and vanish during their transformation. Only moon rings remain in both forms as they are magical themselves. Humans who have changed into merpeople possess this power since their first transformation. Since natural merpeople do not have a human form, they can cast a spell to give them legs with the Full Moon or Moon Rings.
  • Slightly enhanced senses - Mermaids may have slightly enhanced senses suited to life underwater due to living in the sea. To mermaids, land people smell horrible, even the average hygienic human emits this smell but only mermaids can detect it. However, they can get used to the smell. By smelling Rita's supply of squid ink, Lyla could identify where the species of squid came from. According to Lyla, as mermaids are connected to the sea, they can sense a change in the currents, whether a shark is dangerous or if a dolphin will help them find their way home. In H2O: Mermaid Adventures, mermaids have the same range of hearing as dolphins. With this sound, they can hear things humans cannot but their human half allows them to hear sounds cetaceans can't.
  • Durability - Merpeople can swim for days without fatigue. Mermaids are also able to swim at 600 km per hour for long periods of time, something which no human has the endurance to do. However, they only appear to have this ability in merperson form.
  • Mako Mermaids Speed-Swimming
    Speed-Swimming - In water, merpeople also have the additional ability of Speed-Swimming. When a merperson speed-swims their body is enveloped in bubbles that they use as a jet stream to swim quickly. This can be a great advantage when trying to flee from enemies such as another merperson or boats and other watercrafts. It has also been referred to as, "torpedoing." 
  • Aquatic adaptation - Merpeople can adapt and swim in both fresh and saltwater but they prefer to live in saltwater. Depending on where they are born and were raised, mermaids may be resistant to certain elements in that area. Northern merpeople may be resistant to low temperature as they swim in cold waters like the seas around Canada and the Arctic Circle. The Canadian Mermaid wasn't suffering from the cold or hypothermia, even though she was swimming in an area where the temperature was very low and the humans she attacked were dressed in thick clothing to keep warm, further implying the low temperature and Northern merpeople cold resistance. 
  • Zoolingualism - Some natural-born merpeople have the unique ability to understand and speak the language of sea creatures (for instance, dolphins and whales). It is unknown if the ability can be learned, but it is unlikely. Nixie, Sirena, and Rita are known for demonstrating this ability with dolphins, while Mimmi also speaks dolphin, humpback and blue whale, and northern penguin. In H2O: Mermaid Adventures, the main characters gain the ability to speak with all sea creatures, including cetaceans, cephalopods, fish, marine reptiles, and crustaceans.

Merpeople Magic

Mimmi Using Moon Ring

Mimmi using her Moon Ring

Main article: Merpeople Spells

Merpeople have a natural gift for spell making using ingredients found in nature. They make potions to perform things their magic powers cannot like heal wounds, transform animals, grant wishes and neutralize anything, including other spells.

Lewis McCartney found a book, "Mermaid Mythology" that held a recipe for a Mermaid's Potion that could give mermaids the power to grant wishes. It may have possessed more potions like the wish-granting spell.

Mimmi Using Jiao Long Braclet

Mimmi using the Jiao Long Bracelet

Moon Rings are a huge part of mermaid magic and every mermaid is taught how to use one and all receive a ring after they finish Mermaid School. Moon Rings are a vital part of a mermaid's survival as merpeople use them for healing what potions cannot, enhance the natural world for camouflage, grant them human form, and amplify their inherent magical powers. With their rings, mermaids can cast many spells. Mermaids can also craft other magical items like the Jiao Long Bracelet. This has red stones, implying mermaids have altered the magic of the stones for a specific purpose. Rita mentions that only a mermaid can wear the bracelet.


  • Snow Rash

    Sirena and Lyla with Snow Rash

    Snow Rash - Southern merpeople such as Lyla, Nixie, Sirena and Ondina that were born in Southern oceans, have never interacted with snow. If they do end up going into contact with it, it will make them develop Snow Rash, a moss-green rash caused by contact with snow; it seems to be very fatal to Southern merpeople. It is accompanied by itch, fever, and malaise and doctors such as Dr. Blakely couldn't realize what it was. Snow Rash interferes with their powers and prevents them from using Hydro-Thermokinesis and Pyrokinesis to warm themselves. A merperson who tries to use these powers will only generate cold and lower the temperature. It is not known whether a human transformed into a merperson by a Moon Pool also develops the disease. It was first shown in Mako Mermaids. Northern merpeople born and raised in icy waters are immune to Snow Rash and may develop some immunity to the cold too. Western and some Eastern merpeople are immune to Snow Rash too. The only way to cure this allergy is a Dried Seahorse Powder that Rita contains stored within a silver seahorse. To heal, the dust must be sprinkled on the affected part of the skin, and it will immediately disappear.
  • Emma Finds The Coral

    Dangerous Coral

    Fish Fever - A strange, rainbow-colored coral houses a poison that affects both fishes and merpeople. It causes them to be overexcited, but the more the poison seeps into their system, the more ravenous they get. The poison also causes a tremendous mutation in a mermaid's physical form. For Emma: her copper-golden-orange scales turned white and scales even appeared on the skin, her hands became webbed, her nails turned black and later into claws, her skin became more monstrous; her neck sprouted a set of gills, her hair started to turn green, her eyes turned yellow, and she made monster-like noises. She also developed a desire to be wet. Emma was later cured when Lewis sprayed an antidote on her skin, which was developed by Laurie. When a fish affected by coral's poison, its scales will turn white, and they will develop a out of control hunger. Laurie said that if Cleo's fish was not cured in time, he would have died and the same goes for the merpeople.
  • Ambergris


    Ambergris - Is an old substance that at one point in time was used to make beauty products such as ladies perfume. It comes from the intestines of a whale and it can be used to attract mermaids. In "Irresistible", Zane Bennett finds some old ambergris which Nate later tries on. The smell from the ambergris makes him stink but it also makes him literally irresistible to Cleo, Emma and Rikki. Ambergris was also one of the ingredients used in Mimmi's potion of fifty moons to remove Zac's powers.
  • Allergic Reaction - Mermaids seem to have an allergic reaction to a certain substance of aftershave, which cause their powers to blow uncontrollably when they sneeze. Mermaids also had an allergic reaction to a formula Lewis created to allow mermaids to get wet while in human form, and not grow tails. The allergic reaction however only manifested as red spots all over their bodies when mermaids were in their human form. Besides this, Lyla, upon being asked by Dr. Blakely of what sort of allergies she has, she calmly responds with: "Only kelp spores in the Atlantic."
  • Sickness - Merpeople don't get sick, unlike humans. However, they can be infected if they come across a sick land person and can spread it to other merpeople as well. The symptoms involve oozing heat from out of their bodies and breathe fire whenever they sneeze. Rita Santos invented a remedy for such situations after coming across such occasions multiple times. Mimmi, being inexperienced with such situations, tried to concoct a potion, but it only worked temporarily, after which the sick merpeople will feel cold and eventually breathe ice in their sneezes.
  • Dehydration - As sea creatures, merpeople require water to remain healthy. Mermaids have been known to die from drying out. Though magically assuming a human form extends their time on land, they still cannot stay on land forever. Merpeople can die from water deprivation. As mentioned by Sirena, merpeople have died from, "drying out". It is unknown if a human transformed by a Moon Pool would also have this effect as well or suffer from this weakness.

Known Merpeople




  • Aurora
  • Chinese Mermaid
  • Erik's ancestors †
  • Eva
  • Kinder merman †
  • Unnamed Mermaid †
  • Unnamed mermaid ancestor †
  • Unnamed merman ancestor †
  • Unnamed Northern mermaid
  • Unnamed Southern mermaid
  • White Mermaid

Note: † = Deceased


  • Natural-born merpeople do not have a human form, although they have the ability to give themselves one. Since that kind of magic isn't possible without a powerful source of moonlight, this can only be done with a Moon Ring or full moonlight itself. When natural-born merpeople first grow legs, they are naked. They also have difficulty getting used to walking at first but with lots of practice, becomes a habit. 
  • Merpeople, even humans that were transformed into one, feel much better in the water than on the land.
  • It is possible that the amount of time it takes for the transformation to take full-effect can vary depending on the amount of water the merperson came into contact with. For example, if a bucket of water was dumped on a merperson's head or they dove into the ocean, they'd transform immediately. If a merperson came into contact with a normal amount of water (such as spilling a glass of water on oneself), it would take the normal 10 seconds approx. However, just a drop can change them.
  • Water is much more than a mermaid's home. Water can help heal or revive them. However, this only applies to certain illnesses or injuries as it takes more than water to heal a mermaid who is struck by the Moon Ring or the power of the Trident. Mermaids who stay in the sea don't get sick.
  • Merpeople are mortals, like humans.
  • All natural born merpeople have a strong instinct to eat seafood. Humans who were transformed by the Moon Pool do not experience this, apart from when they are under the Moon Spell (which makes them behave like they are real merpeople).
  • It was revealed in Dolphin Tale that natural-born merpeople can speak the languages of sea creatures, as Sirena and Nixie can speak dolphin and Mimmi can speak dolphin, northern penguin, and humpback whale.
  • It is possible that only natural merpeople can make themselves invisible.
  • Merpeople, including natural ones, are said to have a hard time controlling the power of the full moon when they haven't been properly trained. For this reason, they need to learn to concentrate on letting the moon's magic flow through their bodies rather than resist it. After this, they can wander out in the moonlight.
  • The Full Moon's effects on merpeople may be a reference to the mermaids in Peter Pan by J.M. Barrie. In Barrie's story, the mermaids experience a "haunting" change at the "turn of the moon."
  • The dangerous reputation of the Northern Pod may have been inspired by the legends of dangerous, wicked mermaids which are most common in the Northern Hemisphere.
  • It is unknown how mermen reproduce, but they may marry human women. This would explain their land form since natural mermaids need a spell to gain human legs.
  • Zac may be the only full merman in the twenty-first century as he was born the same way as a mermaid.
  • Merpeople are warm-blooded creatures and are able to be seen invisible by heat detecting equipment.
  • Mermaids have great knowledge of the underwater world and know things that marine biologists are unaware of. Their knowledge is limited to the creatures of their oceans. Mimmi was unaware that penguins are only native to the Southern Hemisphere.
  • A few known natural predators of mermaids are orcas and giant squids. Rita uses these as examples of why a mermaid would require a certain power if she ever came across them.
  • Just like in the legends, natural mermaids have a slight streak of vanity and often comb their hair like the classic depictions of mermaids.
  • Natural merpeople tend to be given names with meanings that relate to water in some way, including literal translations to "water", or relating to mythological figures related to it such as gods, goddesses, and spirits.

See also

Merpeople Powers
Merpeople Spells
Gallery: Merpeople