Top 10 Most Rarely Seen Deep-Sea Lifeforms

This deep-sea squid is found in tropical waters around the world and can grow up to 20 cm (8 inches) in length. It has a unique pair of retractable, thread-like filaments that it uses to capture prey. Few species have been documented as rare as this one, with only about 250 specimens recorded since its discovery in 1909. Vampyroteuthis Infernalis is also known for its bioluminescent capabilities, allowing it to emit a reddish glow from its body.

Also known as the blue dragon, this small sea slug is found in tropical waters and can grow up to 10 cm (4 inches) in length. It has a distinctive blue color with yellow spots and is thought to be one of the most venomous sea creatures in the world. Glaucus Atlanticus is rare because it is difficult to find and study, with only about 30 documented specimens recorded since its discovery in the 19th century.

This small deep-sea octopus has ear-like fins that resemble Disney's Dumbo the elephant's iconic ears. It can grow up to 20 cm (8 inches) in length and is found in deep waters around the world. The Dumbo octopus is rare because it has never been observed outside of its habitat, making it a mystery to scientists studying this species.

This massive squid can grow up to 19 meters (62 feet) in length and weigh over 750 kg (1,650 pounds). It is found in the deep waters of the Antarctic and southern Pacific oceans and is one of the largest invertebrates on Earth. The colossal squid was only recently described in 1925 and its habits are still poorly understood.

This deep-sea fish has massive teeth that can grow up to 15 cm (6 inches) long, making it one of the most formidable predators in the ocean. It can grow up to 30 cm (12 inches) in length and is found in deep waters around the world. The Fangtooth is rare because its deep-sea habitat makes it difficult for scientists to study.

This pale-colored shark was discovered as recently as 2004 and can grow up to 60 cm (24 inches) in length. It has a distinctive ghostly appearance, with its body covered in small, bony plates that reflect light. The ghost shark is rare because it is thought to be a deep-sea dweller, and few specimens have been recorded.

This ancient-looking shark can grow up to 2 meters (6.6 feet) in length and has a frilly gill slits that resemble a medieval warrior's cloak. It is found in deep waters around the world and has remained largely unchanged since prehistoric times. The frilled shark was thought to be extinct until it was rediscovered in 2005.

This small fish can grow up to 15 cm (6 inches) in length and is found in deep waters around the world. It has a distinctive fleshy growth on its head that is used as a lure to attract prey. The pygmy anglerfish is rare because it lives in symbiosis with a male parasite that produces sperm, making mating processes difficult to study.

This deep-sea worm can grow up to 2 meters (6.6 feet) in length and is found in the ocean's deepest vents. It has no mouth or digestive system, relying on chemosynthetic bacteria that live inside its body. The giant tube worm is rare because it thrives in an environment with extreme temperatures and chemicals.

This small fish can grow up to 30 cm (12 inches) in length and has a distinctive blue and yellow striped pattern. It is found in deep waters around Europe and has never been seen outside of its habitat, making it one of the rarest species in the ocean.