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@cephalopodsdaily.bsky.social Oct 11, 2026, 6:11 PM

The big-eye jellyhead (Inopinoteuthis magna), in addition to having a very silly name, is thought to be the largest species of cirrate octopus, a group of octopus with small tendrils called cirri, fins and an internal shell.

One specimen of this species had a total length of 1.7 m.

#OCTOtober

@cephalopodsdaily.bsky.social Oct 10, 2026, 6:37 PM

I just know they'd love hot tubs.

Vulcanoctopus hydrothermalis is a small octopus species that lives around deep sea hydrothermal vents. They can handle the heat though, being able to survive in water up to 91°C. They have a mantle length of less than 6 cm and weigh less than 44 grams.

#OCTOtober

A vulcanoctopus hydrothermalis crawling around a rocky hydrothermal vent. It is pale white and has black eyes. Its arms are curled. There is a sea anemone on the right of the image

A vulcanoctopus hydrothermalis octopus walking on the sandy seafloor. It is pale white and has black eyes.

A vulcanoctopus hydrothermalis octopus crawling around a rocky hydrothermal vent. It is pale white and has black eyes. The tips of its arms are curled. There is a sea anemone in the bottom right of the image, and there are several white crabs nearby.

@cephalopodsdaily.bsky.social Oct 10, 2026, 12:31 AM

Argonauts (genus Argonauta) are a genus of pelagic octopuses like to ride around on jellyfish and salps.

Female argonauts have a "shell" that is actually an egg case that they live in. They are also known as paper nautiluses, although true nautiluses are actually named after them.

#OCTOtober

A female Brown Argonaut (Argonauta hians) riding a red bell jellyfish. The argonaut is sitting on the bell of the jellyfish, and the jellyfish is swimming downward, so the whole thing is upside down. The jellyfish has a dark orange bell and light orange arms. The argonaut has a wavy, spiral egg case that it wears like a shell. The egg case is a off white with black or grey on the outer rim. The argonaut itself is mostly in the egg case but you can see its head and part of its arms sticking out of the egg case. Its arms are sucker side out, and it has a bright orange eye with a round black pupil.

A female Noury's Argonaut (Argonauta nouryi) being held by a person in an orange bucket. The octopus is in its "shell". The "shell" is actually an egg case and is white and bumpy. It forms a spiral shape but that is not visible in the photo. The photo is showing the opening where the octopus is. The octopus is a dark red, almost purple, colour with white flesh that just peeks out behind the chromatophores. It has most of its body in the "shell" and its arms are reaching backwards into the shell, exposing the bottom of its arms. The offset two rows of suckers are visible. Its eye is just peeking out from the shell on the left side, at it has a round pupil. On the front right, its siphon is poking out from between its arms and its opening its sort of shaped like a gridiron football, making it look a mouth. If you see the siphon as a mouth, it makes the octopus have a confused, dazed expression.

A male Knobbed Argonaut (Argonauta nodosus) riding a jellyfish. It is very small All of its arms are visible, including its hectocotylus. It is translucent, with its mantle, siphon and arms being clear but its head being white and more opaque. Its eye is round and silvery. The jellyfish is pointed to the right, and the argonaut is hanging onto that side. The jelly is transparent and clear with some orange bits visible through the flesh. There are numerous shrimps (or similar looking crustaceans) swimming around. The water is black.

A Brown Argonaut (Argonauta hians) riding a translucent jellyfish. The argonaut has a spiral "shell" (actually an egg case) that is it wearing, and its mantle is in the egg case, and its arms are reaching back into the "shell." The shell has a wavy series of edges. The parts of the arms that are exposed have their suckers sticking out. Its mantle is sticking out on the left side. The argonaut has round silvery eyes, its body is white with purple chromatophores, and a beige shell. The jellyfish is clear and has frilly edges. The background is dark.

@cephalopodsdaily.bsky.social Oct 8, 2026, 5:28 PM

Coconut Octopuses (Amphioctopus marginatus) are known to use tools. They will carry around shells in order to deploy them as a mobile shelter. It's nice to have some armour when you're a soft and squishy mollusk

They also are known to sometimes walk around on two limbs. Take that Plato!

#OCTOtober

A Coconut Octopus (Amphioctopus marginatus) sitting in a horizontal bivalve shell on the sea floor, and it is lifting the top half of the shell with one arm. The octopus looks very annoyed, and is staring at the camera. The octopus is a dark brownish red, with light orange on the bottom of its arms and white suckers. The inside of the shell is white, and the outside of the shell has dark red or orange stripes alternating with white ridges.

A Coconut Octopus (Amphioctopus marginatus) inside a glass bottle trying to pull in a crab it has caught, but the crab is too big. The octopus has its arms outstretched and grabbing the sides of the bottle. The octopus is off white with some dark brown through its eyes. A lot of its suckers have a light blue tinge. There is a bivalve shell in the bottle. The crab is larger than the octopus. It appears to have a crack in its shell, probably where the octopus bit it. It is facing away from the camera. Its left arms and a small part of its body are pulled into the bottle. It has a mottled batter on its body with some blue at the ends of its arms. The sea floor is sandy.

A Coconut Octopus (Amphioctopus marginatus) hiding in a glass jar lying in the seabed. The photo is taken facing the opening. The octopus is sticking its head and the top of its arms out of the jar. The suckers are clearly visible and the octopus is giving puppy dog eyes. The rest of its arms and body is in the jar.

A Coconut Octopus (Amphioctopus marginatus trying to leave its collection of shells for a larger shell, which contains another coconut octopus. The first octopus is exposed, and is straddling between the two sets of shells. The original set appears to be three, smallish shells. Two arms are reaching into the new shell. The octopus is purple, with little beige bits breaking up the purple. Its sucked are visible. Its mantle is round. The second octopus is is sitting in two, large mismatched shells. It is quite snug, with its suckers holding on to both shells. It is purple, with a lavender colour around the eyes and white around the suckers.

@cephalopodsdaily.bsky.social Oct 7, 2026, 5:12 PM

Blue-ringed octopuses (genus Hapalochlaena) are the only cephalopod whose venomous bite is potent enough to kill a human.

However, they are docile and won't bite unless provoked or hunting. So keep your distance and don't make them feel threatened or be a crustacean and you'll be safe.

#OCTOtober

A Greater Blue-ringed Octopus (Hapalochlaena lunulata) swimming against a black background. Its mantle is relatively thin and the tip gets much thinner. The end of the mantle is out of focus. The octopus is looking at the camera, and it appears to be moving to the upper right, as most of its arms are trailing in that direction. One arms is going back and another is in front of its face and curving around. The arms have two rows of suckers that are offset. The octopus is yellow with many blue iridescent rings.

A photo of a southern blue-ringed octopus (Hapalochlaena maculosa) striking a pose. It is leaning to the left (camera's left), with left arm raised up and with half of it curled, and another one of it's left arms pointing left and with a quarter of it curled. The octopus is a pale brown-yellow with black patches with iridescent blue rings in the centre.

A photo of a Blue-lined Octopus (Hapalochlaena fasciata) on the sandy sea floor among sea grass. The octopus appears to be moving, with its arms curled backwards. Its mantle is tear drop shaped or like a milkweed seed pod, gong to a rounded point. It is has its papillae raised. It is a pale yellow colour, with black or dark brown areas. Inside the dark areas, are iridescent blue circles or lines.

A Greater Blue-ringed Octopus (Hapalochlaena lunulata) walking. Two arms are touching the ground, but its other arms are tucked close and curled. It is yellow, with some white on the the tip of its mantle, head and centre upper arms. It is covered in iridescent blue rings. It has bumpy skin due to having its papillae raised.

@cephalopodsdaily.bsky.social Oct 6, 2026, 5:22 PM

Mimic Octopuses (Thaumoctopus mimicus) are known for the fact they mimic several different kinds of animals, including sea snakes, flatfish, lionfish, anemones and more. They also seem to choose their disguise based on the predator they are trying to fool.

#OCTOtober

A Mimic Octopus (Thaumoctopus mimicus) sityting on the sea floor. Its mantle is hanging behind it and its arms are holding it up and have the webbing partially inflated. It is facing forwards, towards the camera and its two fleshy horns above each eye are flopping to the left, pushed by the current, making the octopus look rather silly. Its arms are also being pushed left. The sea floor is a grey sand with many small rocks.

A Mimic Octopus (Thaumoctopus mimicus) stick out of the sand with an interesting pose. It is some of standing up, with most of its arms going straight down all oriented sucker forward, its mantle hanging behind, and its eyes on top. Its two centre arms, which are on top on the outside in this pose, go out and curve back forming a sort of hood shape. It is unclear why the octopus is in this pose or if it is trying to mimic something. The octopus is brown with some white, and white on the underside of its arms. The arms have two rows of suckers in an offset zig-zag pattern. The sand is greyish.

A Mimic Octopus (Thaumoctopus mimicus) sitting in the sand. Its head and mantle are visible, and long "horns" extend from above each eye. Its arms are wavy and extend behind it. It has a white and brown striped pattern.

A Mimic Octopus (Thaumoctopus mimicus) going across the sandy seafloor which mimicking a zebra sole. It has body pressed flat against the seafloor, giving it a wide and flat appearance. It has an alternating maroon and pink/white pattern, but mostly maroon. Its arms have alternating stripes of maroon and pink, with its white suckers visible.

@cephalopodsdaily.bsky.social Oct 5, 2026, 8:17 PM

The Māori octopus (Macroctopus maorum) is one of the largest octopus species found in New Zealand and Australian waters.

They also have arms that are long even for a large octopus. They have a max mantle length of 30 cm, but their longest pair of arms can have an arm span of over 3 m!

#OCTOtober

A close up of a Maori Octopus (Macroctopus maorum) focused on its head. It has dark red and bumpy, wrinkly skin skin. One of its eyes is visible and is staring directly at the camera, making it look as if it has a judgmental expression.

A Maori octopus (Macroctopus maorum) sitting in among seaweed and extending its long arm at the camera. The seaweed looks like a bush, and its probably attached to a rock that the octopus is sitting on. The octopus is partially concealed, with its head and part of its mantle sticking out. The arm is rather long, although it might look a bit longer from how the camera was set up. It extends from the seaweed, curving down, then curving up while twisting, then going back down and then turning right and then steeply up. The tuckers are clearly visible as they are facing the camera at the end. They are cream coloured, contrasting with the brown of the rest of the octopus. There are two rows of offset suckers, and they are appear to have a brown rim with little fringes. There is not great visibility in the water in the background, but some pillars are visible in the background, possible part of a pier.

A Maori octopus (Macroctopus maorum) sitting among some rocks. It is partially between a gap between to rocks, and it is facing into the gap and away from the camera. The octopus has its papillae raised, so its mantle and head look very bumpy. It has yellow eyes. It has a dark purple colour on its mantle and head, with its arms being a mix of purple and white, with white spots.

A Maori Octopus (Macroctopus maorum) on the seafloor. It is reaching towards the photographer, with two of them lifted up and curving back, exposing their suckers towards the camera. The two arms take a significant part of the photo, so they make it look like the octopus is trying to block the camera. The octopus is dark orange and has a wrinkly texture with lots of larger bumps. There are fish swimming in the background and the sea floor is covered in medium sized rocks.

@cephalopodsdaily.bsky.social Oct 5, 2026, 2:59 PM

A dumbo octopus for #OCTOtober

@cephalopodsdaily.bsky.social Oct 4, 2026, 10:08 PM

As you probably guessed, the Seven-armed octopus (Haliphron atlanticus) has EIGHT arms!

The males' hectocotylus (specialized mating arm) is curled up in a pouch which, along with their large, gelatinous bodies, makes it look like only have seven arms, hence their common name.

#OCTOtober

A seven-armed octopus (Haliphron atlanticus) swimming while extending its arms. Webbing is between its arms and the tips of the arms are curled outwards. The rest of the octopus is gelatinous

A seven-armed octopus (Haliphron atlanticus) swimming while holding a jellyfish in its arms. It's arms are curled away from the jellyfish. The octopus is quite gelatinous and has a white colour, and the jelly fish is golden with short stingers.

A view of a seven-armed octopus's (Haliphron atlanticus) mouth. Its arms are spread out, showing the messy row of suckers and webbing. You can see the octopus's eight arms. The octopus is orange with white suckers. It is swimming in a kelp forest.

A seven-armed octopus (Haliphron atlanticus) swimming towards the camera while extending its arms. Webbing is between its arms and the tips of the arms are curled outwards. The rest of the octopus is gelatinous. It is pink

@cephalopodsdaily.bsky.social Oct 3, 2026, 7:22 PM

Someone get them some paint and an easel, STAT!

The Brushtip Octopus (Eledone schultzei) has brush-like tendrils at the tips of its arms, hence its common name. The only arm that doesn't get a brush is the hectocotylus, the specialized mating arm that males have.

#OCTOtober

A Brushtip Octopus (Eledone schultzei) crawling around some large rocks. Its arms are spread out and feeling all around. It has reddish orange wrinkly skin.

A Brushtip Octopus (Eledone schultzei) in a white plastic container. It is small, so it appears to be a juvenile. It is dark red. Its mantle is leaning back resting on the bottom of the container, while its arms go out into different directions and curve in different ways

A Brushtip Octopus (Eledone schultzei) sitting on some rocks. Its arms are held under it except for one arm which is reaching back behind the rock it is sitting on.. It has a light brown colour and bumpy skin.

A drawing deplicting the brush like tips of Eledone schultzei's arms from "ROPER AND MANGOLD: REDESCRIPTION AND DESIGNATION OF APHRODOCTOPUS" page 59.. Note the scientific name is listed in the caption is Aphrodoctopus schultzei, a synonym for Eledone schultzei.
Caption text: Figure 1. Aphrodoctopus schultzei, holotype, 49 mm mantle length. a-b: Modification of sucker rims into digitate processes on tip of right arm IV. a. Oral view. b. Lateral view. c. Hectocotylized right arm III; ligula length, 4 mm.

@cephalopodsdaily.bsky.social Oct 2, 2026, 5:14 PM

East Pacific Red Octopuses (Octopus rubescens) share their range with the Giant Pacific Octopus (Enteroctopus dofleini) have a similar appearance, so they were originally thought to be young Giant Pacific Octopuses

Even as paralarva, they look very similar, like a little metroid.

#OCTOtober

A juvenile East Pacific Red Octopus (Octopus rubescens) only about 2.5 cm long sitting on something (Maybe a shell) and striking a pose. There is a black background and the octopus is a beautiful red and orange.

A tiny juvenile East Pacific Red Octopus (Octopus rubescens) sitting on a piece of wood sticking out of the sandy sea floor. There is green plant matter at the bottom of the wood. The octopus is less that 2 cm long. Its arms are below it, go out and then curl. The octopus has its papillae raised, giving it a bumpy texture. Its mantle goes to a rounded tip, and the mantle is resting behind its head on its arms. The octopus has a line shaped pup that it is tilted slightly down, giving it a determined appearance. The octopus is a beautiful ruby red, with some beigish red areas on top.

Three East Pacific Red Octopus paralarva (Octopus rubescens) piled up in the corner of a clear container. They are translucent with orange chromatophores on their mantle and arms and you can see organs inside the mantle. There is a ruler in the container and you can see the octopus are about 8 millimetres in length, although two are on a diagonal and so only appear to be 5 to 6 millimetres in length

A East Pacific Red Octopus (Octopus rubescens) sitting in a shallow plastic container that is held by a person. It looks like it was just collected while tide pooling. The octopus is sort of sitting up, so it has its head and half of its mantle out of the water, with its arms mostly in the water. It has two rows of suckers. The octopus is dark red, with some orange at the ends and undersides of its arms. The parts out of the water look shiny. The background is out of focus, but you can see water, rocks and pink/purple sea plants.

@cephalopodsdaily.bsky.social Oct 1, 2026, 9:07 PM

The glass octopus (Vitreledonella richardi) has a body that is almost completely transparent. They live water column instead of on the sea floor, so this helps them avoid being seen by predators.

The only parts of its body that are opaque are its eyes, digestive tract and chromatophores

#OCTOtober