Nudibranch Spanish Dancer – the Most Iconic & Beautiful Sea Creature

This mesmerizing creature is one that divers around the world strive to see during their night dives. Let’s uncover some fun facts about this captivating species:

 1. Spanish dancer earned its name due to its graceful, rhythmic movements that resemble a flamenco dancer’s twirling skirt. 

2. These nudibranchs are known for their striking coloration, featuring bright red or orange bodies. Their vibrant appearance serves as a warning to potential predators that they are toxic or distasteful.

3. Spanish dancers are quite large for nudibranch standards, reaching lengths of up to 60 centimeters. Their size, combined with their vivid colors, makes them a popular subject for underwater photographers. 

4. Unlike most nudibranchs, Spanish dancers are not strictly herbivorous. They primarily feed on toxic sponges, which contain chemicals that they can store in their own bodies for defense.


5. During mating, Spanish dancers engage in a beautiful courtship dance involving synchronized movements. They release their eggs and sperm into the water, where fertilization occurs externally. 

6. Nudibranchs, including Spanish dancers, are hermaphrodites, meaning they possess both male and female reproductive organs. This allows them to mate with any other mature individual they encounter.

More about Spanish Dancers & other beautiful nudibranchs you can find in the photo guide Nudibranchs of the Coral Triangle

5 Things You Might not Know About Rays

Rays are fascinating creatures that inhabit our oceans and have some surprising characteristics.

Round Ribbontail Ray

1. Rays Are Not Actually Fish: Contrary to popular belief, rays are not classified as fish. They belong to a distinct group of cartilaginous fishes called elasmobranchs, which also includes sharks. 

2. Electric Rays: Some species of rays, known as electric rays, have the incredible ability to generate and discharge electric shocks. These shocks are used for various purposes, such as hunting prey and self-defense.

Blackspotted Electric Ray

3. Winged Swimmers: Rays are renowned for their unique flat body shape, which resembles a pair of wings. This design allows them to gracefully glide through the water, effortlessly maneuvering and often appearing as if they are flying.

 4. Venomous Stingers: Many ray species possess a venomous stinger located at the base of their tail. These stingers are primarily used for defense and can cause painful injuries if stepped on or accidentally touched.

Spotted Eagle Ray

5. Rays Reproduce Differently: Unlike most fish, rays have a unique reproductive system. Instead of laying eggs, female rays give birth to live young. These pups develop within the mother’s body and are nourished through a placental connection until they are ready to be born. 

Next time you encounter a ray, remember these fascinating facts and appreciate the remarkable diversity of these mesmerizing creatures in our oceans!

More about rays you can find in the photo guide Coral Reefs Maldives

Some Intriguing Facts About Fascinating Ocean Animals Called Flatworms

Make sure to read until the end. The most intriguing fact awaits you at the end.

 1. Diversity. Flatworms represent a diverse group of invertebrates that come in a variety of colors, shapes, and sizes. Known over 20,000 of flatworm species.

2. No Body Cavity. Flatworms lack a body cavity between their gut and body wall. This unique feature gives them a flat, ribbon-like appearance and inspired their common name. 

3. Regenerative Abilities. If a flatworm is cut into several pieces, each piece has the ability to regenerate into a complete organism. This ability to regrow missing body parts is truly extraordinary! 

4. Hermaphroditic Nature: Most flatworms are hermaphroditic, meaning they possess both male and female reproductive organs. This enables them to engage in reciprocal mating, where two individuals fertilize each other’s eggs. 

5. Predatory Behavior: Some flatworms are voracious predators, feeding on small invertebrates and even other flatworms. They use their muscular bodies and adhesive secretions to capture and consume their prey.

6. Unique Reproductive Behavior: In certain species of flatworms mating involves a peculiar behavior called ‘penis fighting.’ During this process, two flatworms extend their long, extendable penises and engage in a battle of sorts. The goal is to inseminate the opponent while avoiding being inseminated in return. It’s an intense and unusual reproductive strategy observed only in the world of flatworms!

 Flatworms are truly captivating ocean animals, showcasing a range of adaptations and behaviors. Their unique biology and ecological roles make them a fascinating subject of study for marine enthusiasts and scientists alike!

More about them you can find in the Marine Flatworms of the Tropical Indo-Pacific

The Weird and Wonderful World of Marine Worms

A new book by Andrey Ryanskiy has just been published!

Marine worms are recognized world champions in biodiversity. This book is the first photo guide to these secretive and often strange animals. The book is based on photographs taken by the author, as well as his friends – citizen scientists and professional marine biologists.

It is designed for the general public interested in marine life. The book is also of interest to scuba divers and underwater photographers interested in identifying their underwater finds. This photo guide should also assist marine biologists and students in the initial identification of collected marine worms.

The book covers the region from the Red Sea, East and South Africa to Hawaii, Marshall Islands and Guam.

Inside the book:

– Over 820 full color photographs of 440+ species;

– Particular attention was paid to color variations, for some species up to 10 photos were added;

– Live photographs of most of the species have never before appeared in field guides or popular books;

– Convenient pictorial guide at the beginning and genera index at the end of the book.

Find all purchase links here

Red Sea Marine Life Book has just been published

Reef ID Books is delighted to announce the launching of a new marine life guide Red Sea Marine Life. The book continues Reef ID Books’ commitment to publishing first-class marine life guides for underwater photographers, snorkelers and marine biologists.

Some reasons why you need to buy Red Sea Marine Life Book:

  • A comprehensive pictorial guide: 2900 full color photographs of 2100+ species, including 810+ fish species, 250 cnidarians (corals and relatives) and near 350 species of nudibranchs and sea slugs.
  • New species of fish, nudibranchs, sea slugs and other invertebrates were discovered by the author during the work on this book.
  • Several well-known Western Pacific species have been recorded for the first time in the Red Sea.
  • Live photo of hundreds of species have never before appeared in field guides or popular books.
  • The book covers the region from the Aqaba and Eilat to Farasan Islands, South Sudan and Erithrea.
  • Red Sea Marine Life serves to fill a gap in the general public’s understanding of Red Sea marine life in the two decades since the previous guides were published.
  • This book does provides its readers with basic information about the biology and taxonomy, serving mainly as a visual guide to their identification.
  • Convenient pictorial guide at the beginning will help readers navigate through the book.

Find all purchase links here.

Some animals can chop off their own heads!

DID YOU KNOW that Elysia marginata is capable of decapitating itself when its body becomes infected with parasites?

Sounds fantastic, but it’s true!

What’s even more bizarre, the head gets around fine without its body. In three weeks, it regenerates a new body, perfectly functioning and parasite-free.

Elysia marginata

“We’ve known for a long time that sea slugs have regenerative capabilities, but this really goes beyond what we had thought,” said Terry Gosliner, senior curator of invertebrate zoology at the California Academy of Science.

To “puff up” is dangerous for pufferfish: myth or not?

Pufferfish will “puff up” as a defense mechanism if they are threatened. A shape that is more than double its original size, round and sometimes covered in spines is much more difficult to bite and isn’t very appetizing to a predator. 

However, just as people should stretch before exercising to avoid injuring themselves, puffers need to stretch out their muscles as well. Inflating yourself full of water so that your skin is stretched tight can be very painful, especially if your muscles aren’t used to it. Even though they sometimes do it just to stretch, puffing up often can be stressful for a puffer. So, it’s best if they do it only when they need to. 

Cyclichthys orbicularis.

Divers! Please avoid frightening puffers deliberately! It sometimes could be dangerous for them.

5 facts you didn’t know about pygmy seahorses.

Hippocampus bargibanti

All seahorses, including pygmies, are part of the family Syngnathidae. Ever since they were first discovered in 1969, pygmy seahorses have become stars of the reef and attract hordes of underwater photographers. 

So what do we know about pygmy seahorses?

  1. Pygmies range in size from 1.4 – 2.7cm, from the snout to the tip of the tail. Human finger nail to toe nail in size.
  2. Like other seahorses, it’s the male pygmy that becomes pregnant. He gives birth to around a dozen young after a gestation of 10-14 days.
  3. They feed on tiny crustaceans that share their local habitat.
  4. Pygmy seahorses differ morphologically from all other seahorses, possessing a single rather than paired gill openings in addition to a brood pouch located on the trunk, rather than the tail.
  5. They don’t have eyelids and are sensitive to light (photographers please note!).
Hippocampus waleananus

Want to know more about Pygmy Sea Horses and other fishes of Indo-Pacific region? Check photoguide Reef Fishes of the Coral Triangle by A.Ryanskiy.

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5 facts you didn’t know about Sea hares

Sea hare is any marine gastropod of the family Aplysiidae (subclass Opisthobranchia, phylum Mollusca).Sea hare is characterized by a shell reduced to a flat plate, prominent tentacles (resembling rabbit ears), and a smooth or warty body.

Petalifera ramosa
  1. Sea hares eat large seaweeds. Their color is diet-derived from the pigments of the algae.

2. This amazing invertebrate grows up to 16 inches in length!

3. All are simultaneous hermaphrodites with fully functional male and female reproductive organs. 

4. As they commonly occur in quite crowded numbers during the mating season, it often leads to chains of three or more sea hares mating together. 

5. To protect themselves they release a noxious ink that irritates the would-be predator and stops them in their tracks, in much the same way a skunk protects itself.

Aplysia parvula

More about Sea Hares you can find in the photoguide Nudibranchs of the Coral Triangle by A.Ryanskiy & Y.Ivanov.

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5 facts you didn’t know about frogfishes.

Latin name of the family is Antennariidae. There are about 47 known species of frogfish worldwide. Fascinating to divers and deadly for its prey, the frogfish is the ocean’s master of aggressive mimicry.

  1. Many of them can change color over time to camouflage within their surroundings. Unlike the chameleon, they are unable to change its color quickly. The process usually takes several weeks.
  2. Striated, or hairy, frogfishes usually mimic algae or soft corals, but can also mimic venomous black urchins.
  3. Their attack is amongst the fastest in the world, being able to trap prey in 0.006 seconds!
  4. The frogfish lacks a swim bladder. This structure is found in most swimming fishes; it maintains their buoyancy in a similar manner to a diver’s BC.
  5. Juvenile painted frogfish mimic toxic nudibranchs. Because of this behavior, they have little to fear from their own predators while being ignored by their prey, allowing easy ambush.