The Hawaiian day octopus (Octopus cyanea), called heʻe mauli in Hawaiʻi, is a daytime reef hunter that eats crabs, shrimp, mollusks, and small fish. Around Maui, it uses coral heads, rocky ledges, and rubble for shelter and can rapidly change its color, pattern, and skin texture. Despite its local name, this species also lives elsewhere in the tropical Indo-Pacific.
Main takeaways:
Aloha! An octopus can be right in front of you on a Maui reef and still look like part of the landscape. The Hawaiian day octopus changes its color, pattern, and skin texture as it moves among coral, rocks, and sand. Understanding its camouflage, feeding habits, and life cycle makes an encounter more interesting, even when all you notice at first is an eye peeking from a crevice.
Get to know heʻe mauli, from its eight flexible arms and changing appearance to its reef habitat, diet, and short life cycle.
| Topic | Details |
|---|---|
| Common names | Hawaiian day octopus, day octopus, and big blue octopus |
| Hawaiian name | Heʻe mauli; heʻe is a general Hawaiian name for octopus |
| Scientific name | Octopus cyanea |
| Animal group | A cephalopod mollusk, related to squid and cuttlefish |
| Size | Arm span can reach about 3 feet, or 0.9 meters |
| Geographic range | Tropical Indo-Pacific reefs, including Hawaiʻi. Despite its local name, it isn’t found only in the Hawaiian Islands. |
| Reef habitat | Coral reefs, rocky ledges, crevices, and rubble, with sheltered dens used between foraging trips |
| Activity | Forages during daylight, unlike many octopus species that mainly hunt at night |
| Diet | Crabs, shrimp, mollusks, and small fish |
| Arms and suckers | Eight arms with suckers along their length, rather than tentacles with suckers concentrated near the tips |
| Camouflage | Rapidly changes color, pattern, and skin texture to blend with its surroundings. A color change alone doesn’t indicate distress. |
| Hearts | Three: two pump blood through the gills, and one supplies the rest of the body |
| Lifespan | Often reported as roughly 12–15 months, although lifespan varies with environmental conditions |
| Early life | Tiny hatchlings called paralarvae initially live in the water column before settling into bottom-dwelling reef life |
| Viewing tip | Observe without touching, chasing, feeding, or blocking its shelter. If it retreats as you approach, stop moving closer and give it space. |
Note: Size and lifespan vary among individuals. Camouflage can make an octopus difficult to notice even in clear water, and sightings aren’t guaranteed.
The Hawaiian day octopus, also known as Heʻe mauli, is a reef octopus found in Hawaiian waters. Its scientific name is Octopus cyanea, and unlike many octopus species, it’s active during the day. That gives Maui snorkelers a chance to see one hunting, hiding, or blending into the reef when conditions are calm and clear.
Heʻe are best known for their incredible camouflage. They can quickly change color and texture to hide from predators, sneak up on prey, and disappear into coral, rock, or rubble. They’re also flexible, intelligent animals with soft bodies that can squeeze into small reef cracks and dens.
In Maui’s reef ecosystem, the Hawaiian day octopus plays an important role as both predator and prey. It hunts crabs, shrimp, small fish, and mollusks, while larger reef animals may hunt it. For snorkelers, spotting one is a rare treat, but always watch it calmly and from a respectful distance.
Fun Fact: Despite its local name, the Hawaiian day octopus isn’t unique to Hawaiʻi. Octopus cyanea also lives on tropical Indo-Pacific reefs beyond the Hawaiian Islands.
Hawaiian day octopus sightings are never guaranteed, but they’re sometimes spotted around Maui’s nearshore reefs when the ocean is calm and visibility is good. Your best chance is to look slowly near the reef structure rather than swim quickly over the top.
Heʻe like places that offer both shelter and hunting access. Look near reef edges, coral heads, rocky outcrops, lava formations, and sandy rubble zones close to the reef.
They often choose hiding spots with more than one escape route, so don’t block a hole, hover directly above it, or crowd the area.
Because the Hawaiian day octopus is active during daylight, you can spot one during the day. Morning is often best for snorkelers because the water is usually calmer and visibility is better. Late afternoon can also be a good time to watch for hunting behavior.
Sometimes you’ll notice signs before you see the octopus itself. Watch for shell piles near a hole, small rocks arranged around a den, a sudden color change on the reef, or moano stopping repeatedly at the same rock.
Crew Tip: Our team often watches moano when looking for Heʻe. If these fish keep stopping and staring at the same rock or crevice, pause and look carefully. An octopus may be tucked into the reef nearby.
Seeing a Hawaiian day octopus in the wild is exciting, but how you behave matters. The calmer you are, the better your chance of watching natural behavior. Move slowly, keep your fins away from coral, and don’t chase the octopus if it starts to retreat.
Respectful viewing protects the octopus and gives everyone a better chance to enjoy Maui’s reef life without stressing the animals that live there.
Hawaiʻi has several octopus species, but the day octopus and night octopus are two familiar shallow-water examples. They’re separate species, not the same animal changing its habits after sunset.
The Hawaiian day octopus, heʻe mauli (Octopus cyanea), forages during daylight and typically shelters in a den at night. Its appearance changes frequently, but brown and tan mottling can help it blend with reef surfaces.
Look for a relatively robust body, textured skin, and arms moving among rocks, coral heads, and rubble. Rather than searching for one fixed color, watch for the animal’s shape and how it moves through its surroundings.
The night octopus, also called the white-striped octopus (Pinnoctopus ornatus), mainly hunts after dark and shelters during daylight. Older guides may list it as Octopus ornatus or Callistoctopus ornatus.
Its recognizable appearance includes a reddish body, paired white spots along the arms, and short white stripes on the mantle, the body section behind the head. Its front arms are particularly long. These markings and proportions offer more useful clues than the sighting time alone.
A daytime reef encounter may suggest a day octopus, but it doesn’t confirm the species. Compare body proportions, skin texture, and the arrangement of spots or stripes, rather than relying on color alone. Both species can change their appearance.
If you’re unsure, a photo taken without approaching or disturbing the animal can help you identify it later.
The Hawaiian day octopus generally avoids people, but it has a strong beak and can bite if handled or threatened. Observe without touching, feeding, chasing, or cornering it. If it retreats as you approach, give it space rather than following it.
The Hawaiian day octopus grows quickly and has a short life, often reported as roughly 12–15 months. Its life cycle includes a drifting early stage before it settles onto the reef.
After mating, the female lays strings of tiny eggs inside a sheltered den. She guards and tends them, moving water over the eggs to supply oxygen and help keep them clean. During brooding, she generally stops feeding and devotes her remaining energy to protecting the developing young.
Newly hatched day octopuses don’t immediately live like the adults snorkelers see on the reef. These tiny hatchlings, called paralarvae, initially live in the water column, where they feed on small prey and can disperse with ocean currents.
This drifting stage lasts for weeks before surviving young settle into bottom-dwelling life.
After settling, juveniles use reef crevices, rocks, and rubble for shelter. They grow rapidly, hunt small animals, and use camouflage to blend with their surroundings. As they get larger, their diet includes crabs, shrimp, mollusks, and small fish.
Adults spend much of their time foraging or sheltering in dens. They’re generally solitary, although they interact during mating.
The female’s brooding period marks the final stage of her life, and she dies after her eggs hatch. The next generation begins its own journey in the water column before eventually settling onto the reef.
The Hawaiian day octopus relies on camouflage, shelter, and quick escapes to avoid predators. Its defenses work together to help it blend into the reef or disappear into a nearby crevice.
Specialized pigment-containing structures called chromatophores expand and contract under muscular control, rapidly changing the octopus’s visible color and pattern. These changes help it blend with coral, rock, sand, and rubble.
Color changes also play a role in communication and other normal behavior. A sudden change alone doesn’t mean an octopus is frightened or that a snorkeler is too close.
The octopus can also raise or flatten muscular projections called papillae. These change its skin from relatively smooth to bumpy, helping its outline resemble the surrounding reef.
That combination of color, pattern, and texture can make an octopus difficult to distinguish from a rock, even when it’s in plain sight.
Its soft, flexible body allows it to squeeze into narrow spaces between rocks and beneath reef ledges. Its hard beak limits how small an opening it can pass through.
A sheltered den provides a place to rest between foraging trips and retreat from danger.
When it needs to escape quickly, an octopus can force water through a muscular tube called a siphon, propelling itself in the opposite direction. It may also release ink that helps distract or confuse a predator while it gets away.
If an octopus retreats as you approach, give it space rather than following it or trying to draw it back out.
In Hawaii, Heʻe has cultural meaning beyond its role on the reef. Maui Ocean Center notes that the octopus is associated with Kanaloa, the Hawaiian deity of the ocean, and that heʻe appears in traditional knowledge connected to the sea.
There’s also a Hawaiian saying, Pua ke kō, kū mai ka heʻe, which refers to sugarcane flowering and the appearance of octopus. It reflects how people observed seasonal signs in nature and connected land, ocean, and food gathering.
Today, Heʻe is still respected as both a reef animal and part of local culture. For visitors, the best way to show that respect is to observe from a distance, avoid touching marine life, and learn before entering the water.
The Hawaiian day octopus is listed as Least Concern globally, but that doesn’t mean every local reef is free from pressure. Heʻe depend on healthy reef habitat, and local populations can still be affected by reef damage, poor water quality, fishing pressure, and careless wildlife viewing.
Small choices make a difference. When snorkelers give marine life space and protect the reef, animals like the Hawaiian day octopus have a better chance to thrive.
The Hawaiian day octopus, or Heʻe, is one of Maui’s most fascinating reef animals. With its quick camouflage, curious behavior, and hidden reef dens, it’s a special sight for any snorkeler lucky enough to spot one.
If you see a Heʻe while snorkeling, the best thing you can do is slow down, keep your distance, and let it move naturally. Don’t touch, chase, poke, feed, or block its escape route. Respectful viewing helps protect the octopus and keeps Maui’s reefs healthier for everyone.
Use these resources to learn about Hawaiian day octopus identification, camouflage, life cycle, conservation, and cultural significance. Before snorkeling in Maui, check current ocean conditions, water quality advisories, and safety guidance.
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