The Portuguese Man O’ War looks like a jellyfish, but surprise — it’s actually a whole team of tiny creatures working together, like the world’s weirdest roommates. Its bright, balloon-like float bobs on the ocean surface while long tentacles dangle below, armed with stings strong enough to stop fish in their tracks. Sailors once thought it looked like a battleship at sea, which is how it got its fancy name. Just don’t try to “pop” it like a beach ball — it’s more shocking than fun!

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Sand dollars may look like ocean cookies, but don’t take a bite — they’re actually relatives of sea urchins! When alive, they’re covered in tiny purple spines that move like bristles on a brush, helping them crawl around on the sandy sea floor. After they wash ashore, the sun bleaches them white, which is why beachcombers love collecting them. Some people even say the five-pointed pattern on top looks like a flower, making it nature’s own seashell art.

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The West Indian Manatee is basically a floating baked potato with flippers and it’s adorable. These gentle giants can grow up to 13 feet long and weigh over 1,000 pounds, yet they spend their days munching on sea grass like underwater lawnmowers. Despite their size, they’re surprisingly graceful swimmers, cruising at a relaxed 5 mph. Manatees have no natural predators unless you count boats, which they sadly don’t see coming due to their tiny peepers. Fun fact: they’re related to elephants, which explains their wrinkles and excellent taste in snacks. 

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The purple sea urchin may look like a spiky little pincushion, but it’s actually a slow-moving, algae-munching powerhouse. With teeth strong enough to chew through rock it’s basically the underwater version of a tiny, spiny bulldozer. Despite having no eyes, it can still sense light—talk about mysterious skills. These creatures play a big role in keeping kelp forests in balance, though sometimes they get a little too snack-happy and turn into kelp-munching maniacs.

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While it cannot fly, the Flying Gurnard is a spectacle for observers. Its name comes from its ability to seemingly glide through the water. This tropical/sub-tropical fish has the ability to change the color of its large fins in order to scare off predators or attract a mate. 

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This fresh water species is the largest amphibian known to man. The largest known species can grow up to 5.9 feet (1.8 meters). The Giant Salamander is native to parts of China and Japan. Like other species of salamanders, it can fully regenerate lost limbs. This includes nerves, muscles, and bones. 

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Found in the Pacific Ocean, this large jellyfish has tentacles that can reach up to 20 feet (6 meters) in length. The Black sea nettle is purple or brown in color and only has a mild sting. This impressive creature does not swim, but instead uses ocean currents to drift around. 

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This creature has been around for over 500 million years. Nautili are found in the depths of the Pacific Ocean. The Nautulis has the ability to change the amount of gas in its shell. This allows it to quickly maneuver between different depths. The Nautilus has up to 90 tentacles to make capturing prey easier. 

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The Blue Dragon sea slug is found worldwide. Despite being tiny, it fearlessly feeds on jellyfish and siphonophores like the Portuguese Man o' War. It's best to view the Blue dragon from a safe distance to avoid a potentially painful sting. 

Sylke Rohrlach from Sydney 

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These pajama sharks inhabit the shallow Pacific Coastal waters of North America. They are very timid around people. Leopard Sharks give live birth rather than laying eggs. This is known as viviparous reproduction.

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The Axolotl is a rare aquatic salamander native to the lakes of Mexico, especially Lake Xochimilco. Known for its “smiling” face and feathery gills, it’s famous for never fully growing up—a condition called neoteny, where it keeps its larval features even as an adult. Axolotls can regrow limbs, spinal cord, and even parts of their heart and brain, making them important in medical research. Sadly, they’re critically endangered in the wild due to habitat loss and pollution, but they’re common in labs and aquariums.

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