The blue-ringed octopus is 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 and certain areas of the Pacific ocean. The blue-ringed octopus bite contains tetrodotoxin (TTX), which can easily paralyze a human for several hours. This is probably the reason for its celebrity, however we can’t rule out a little red carpet fame from the James Bond movie Octopussy.
Blue-Ringed Octopus Facts
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 will also get darker 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 gill.
Species: The name Blue Ring is actually a genus of species with several blue-ringed members. We’re familiar with the well-marked octopuses usually found in 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.
Mating: 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.
Hunting: 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.
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 them during the day, but octopuses are generally known to hunt more at night; that movement is how you’ll spot them.
Octopus Photo Tips
Keep these tips in mind to help you bring home some great blue-ringed octopus photos.
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.
Are you curious about underwater photography?
Check out my Guide to Underwater Cameras.