Blue-Ringed Octopus Facts and Photos

The blue-ringed octopusis one of the deadliest marine animals in the world. A small, well camouflaged mollusk, it is commonly found in rubble reef areas of the Indo-Pacific ocean. A blue ring’s bite contains the neurotoxin tetrodotoxin (TTX), which can easily paralyze or even kill a human. Luckily, these octopus are not violent and would rather hide from humans than bite in defense.

As underwater photographers, we see the most photos of the greater blue-ringed octopus (Hapalochlaena lunulata), although there are 3 other blue-ringed members of the genus Hapalochlaena. The Southern blue-ringed octopus (Hapalochlaena maculosa) and Blue-Lined Octopus (Hapalochlaena fasciata) are much less common than H. lunulata.

Blue-Ringed Quick Facts

  • Common Name: Blue-Ringed Octopus
  • Scientific Name: Hapalochlaena sp.
  • Size: The body can grow to the size of a golf ball once fully mature. Females are larger than males.
  • Lifespan: One to two years.
  • Kingdom: Animalia
  • Phylum: Mollusca
  • Class: Cephalopoda
  • Order: Octopoda
  • Cool Factor: Iridescent blue rings and deadly TTX venom. The blue rings flash more intensely when the octopus feels threatened.
  • Photo Popularity: Top subject for underwater photographers. Go get those photos!

About the Blue-Ringed Octopus

The blue ring earns its name from the many different iridescent blue rings covering its body. Like all octopuses, the blue ring can change texture and color to mimic surrounding habitat, making them very difficult to spot. The general body color is white to yellow and brown, and the rings will glow more intensely if the octopus is stressed and issuing a warning.

Color & Hearts:

The blue-ringed octopus body is normally white in color, but will flush to a dark yellow if the octopus is swimming quickly (e.g. away from disrespectful divers). This is because their circulation isn’t made for these rapid endurance swims. Like all octopuses, blue rings have three hearts: one to pump blood through the body and one to pump blood over each of the two gills.


The name Blue Ring is actually a genus called Hapalochlaena, which is comprised of several blue-ringed members. We’re familiar with the well-marked Greater blue-ringed octopuses usually found in underwater photos, but let’s not forget that the Mototi Octopus should also get a shout out for possessing the same TTX venom even though they sport only one ring on each side.


The female blue ring is larger than the male, although the male is responsible for courting the female and grabbing on. He then uses one special tentacle, the hectocotylus, to deposit sperm packets into her mantle. The female will carry the developing eggs, oxygenating them frequently, under her arms until they hatch. This is a tough job and prevents her from eating, and like all female octopuses, she dies when the eggs hatch.

Blue-Ring Size:

These are very small octopus, growing to about the size of a golf ball. They’re so small and well-camouflaged that you can very easily swim right over them even when scanning for macro critters.

Hunting Facts:

Blue rings are fearsome hunters, crawling across the reef using their tentacles to reach into every nook and cranny for tiny shrimp, crabs and other crustaceans. When the blue ring locates prey they will jump on it, trapping the prey in the webbed part of their tentacles, grabbing it, and moving it to their beaked mouth for a venomous bite.

blue-ringed octopus hunting in manado indonesia
A blue-ringed octopus traps prey while hunting in Manado, Indonesia. It happened so fast I have no clue what it found.
blue-ringed octopus mating
A male and female blue ring prepare to mate in Anilao, Philippines
mototi octopus in lembeh strait
A Mototi octopus stands tall in the Lembeh Strait. Mototi octopus are a different species but use the same TTX venom as the blue rings we commonly see in photos.

Locating a Blue-Ringed Octopus

Finding a blue ring is always exciting. They are challenging to find because of their small size, camouflage and rubble habitat. Your best bet is to let your guide know that you’d like to see a blue ring, and then do an evening or night dive in an area where there have been the most recent sitings.

You’ve honestly got just as much chance of seeing blue rings during the day, but octopuses are generally known to hunt more at night; that movement is how you’ll spot them.

Fun Fact: Blue rings are so camouflaged that I had a workshop guest shoot a photo of a critter and only notice the blue-ring in the background once reviewing the image in his LCD screen. Needless to say, he was stoked and we all shot a few frames.

Where to Photograph Blue Rings

Blue-ringed octopus are endemic to the Indo-Pacific ocean, so most of us will need to plan a dive trip to find them. A focus on underwater macro will give you the best odds of spotting octopus, since your eyes will be trained on the tiny critters.

Be sure to tell your dive guide that photographing a blue ring is at the top of your list, and if you’ve become friends, your guide will hunt for them every time you’re busy shooting another critter. The sign for a blue ring is to make a circle with thumb and index finger and placing the circle up and down your arm… the same pattern the octopus sports.

These are my favorite blue-ringed octopus hotspots:


Maybe it’s because I’ve spent months diving in Anilao, but I’ve seen blue-rings there at quite a few different reef sites. You’ll also be treated to some great mimic octopus action.


The muck capital of the world is home to plenty of blue-rings near rubble reefs. Guides here have a knack for finding wunderpus octopus too!

You never know where you might see a blue ring, so keep your eyes open in Manado, Raja Ampat, Bali, Dumaguete, Puerto Gallera, Milne Bay, and basically any other popular macro destination in the Indo-Pacific ocean. Blue-ringed octopus have even been seen in southern Japan and eastern Australia. Feel free to email me the location you’ve seen a blue ring and I’ll add it to the list!

READ: Packing Underwater Photography Gear

blue ringed octopus hunting in indonesia
A blue-ringed octopus walks across the reef while hunting. This movement is the key to spotting these highly camouflaged marine animals. Shot in Manado, Indonesia.

Octopus Photo Tips

Keep these tips in mind to help you bring home some great blue-ringed octopus photos. Also be sure to brush up on my tips to photograph marine life behavior.

1. Prepare your shot in advance

Most of the time you’ll be with a guide and dive buddies when finding a blue ring, so maximize everyone’s time by adjusting your settings, donning/doffing a diopter, and positioning your strobes before moving in and taking a turn with the subject. This ensures you can shoot 3-4 effective shots before letting your buddy move in for their turn. Here’s the underwater photo gear I use for macro subjects.

2. Don’t chase the octopus

If you chase, the octopus will flush a dark color, which doesn’t look natural in photos. If the octopus swims, it will likely stop very close by. You can then move slowly over and take another shot. If you’re calm and patient, the octopus might even become comfortable and start hunting again without worrying about you. We’re after natural, comfortable posturing and behaviors.

3.  Eye in focus

Octopus have large mantles and even larger tentacles, but the most critical part to keep in focus is the eye(s). Be sure to move your focus point into a position that allows you to compose the shot while ensuring the camera locks focus on the eye. Learn more in my Two Minute Tutorial video on Autofocus.

4. Proper Lighting

Lighting is always important for macro photography. Check out my tutorial on underwater strobe positioning for a complete guide to the best strobe and video light techniques.

5. BONUS – More Critter Info

If you’re an avid photographer, I highly recommend two ID books by Paul Humann and Ned DeLoach. Reef Fish (Tropical Pacific) contains all the fish, and Reef Creature contains everything else. I haven’t met these guys, but they’re the bosses in this department.

Read my guide on the Best Fish ID Books!

blue-ringed octopus in anilao
A blue ring pauses on a small reef ledge in Anilao, Philippines.
blue-ringed octopus mating
Another view of our mating blue-ringed octopus in Anilao, Philippines. Preparing for the shot is essential for taking advantage of fleeting photo opportunities.


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Brent Durand

Professional writer and underwater photo instructor. Brent is an avid diver and surfer, and has led many intensive photo workshops around the world.