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.

juvenile

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

Strange Ocean Animals part 1 – Fringed Worms

The small city of Dahab in southern Sinai is famous for its variety of underwater habitats. Some of them are difficult to find anywhere else. The rounded rocks near the bridge in the middle of town remind me of a couple of dive sites in Anilao. Basura and Mato Point, and it’s not easy to remember the same ones in other places.

Many people, including scuba divers, enter the water every day in this place, next to which there are two diving centers. But no one explores shallow places, less than 2-3 meters deep. Meanwhile, you can find a lot of interesting things there and I will talk about these finds from time to time.

Cirratulids are also called fringed worms because their bodies appear to have a fringe of fine threads along the length. This fringe, in fact, is the gills. Each thread is hollow and is flooded with hemoglobin-bearing blood.

Colonies of Tharyx spp. with a diameter of 12-15 cm, most often found under the edges of stones, 1.5-2 m deep. I used underwater camera with +10 wet lens to make this super-macro shot. To the naked eye, they are tiny underwater creatures with thread-like gills thinner than a human hair.

This is what a larger fragment of a densely populated colony of these underwater creatures looks like. As far as I know, only species of the genus Tharyx of this family drill into calcareous substrates – shells and corals. I have not found any mention of findings of marine worms of this genus in the Red Sea. It is very likely that they have not yet been described by marine biologists.

I thank Dr. Vasily Radashevsky for his help in identifying these strange ocean creatures. More information in my book – The Weird and Wonderful World of Marine Worms

Best, Andrey Ryanskiy

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

Dangerous beauty of the night dive: sea anemone Alicia pretiosa

Alicia pretiosa, Dahab, Red Sea, night dive

Alicia pretiosa is a species of sea anemone in the family Aliciidae and can be found from the Red Sea and Indian Ocean to Central Pacific. This sea anemone is rare, but can sometimes be seen at night, usually on mixed reef slopes near corals and seagrass. It looks very attractive. But touching its long translucent tentacles is highly not recommended. The tentacles are covered with small tubercles, as can be seen in the picture. These are nematocyst batteries and a powerful sting can kill small prey and stun medium-sized prey.

It is generally believed that such sea anemones feed on zooplankton. But this photo shows that their appetite can cope with an impressive predator – a fireworm!

Capturing a fireworm, Ras Abu Galum

The sea anemone Alicia pretiosa comes in a variety of colours. This photo was taken in the Philippines.

Note the small but brave nudibranch – anemone predator!

One of the most beautiful Aeolid nudibranchs feeds on this extremely dangerous sea anemone – meet a brave Limenandra barnosii!

Limenandra barnosi, Anilao

I still have to find a Limenandra barnosi in the Egypt Red Sea, where I live.

More information about nudibranchs you can find in the Nudibranchs of the Coral Triangle book

Best Regards, Andrey Ryanskiy

Giant Moray and its Brave dentist

Giant Moray and Common Cleanerfish

The job of a dentist cleaning teeth only seems dangerous in this case. A moray eel will never offend its Cleaner Wrasse. Cleaner Wrasse eats the parasites in Giant Moray mouth.

Small Gubal Island (Egypt Red Sea) is interesting for its dense fish population. You can meet up to a dozen giant moray eels of decent size during a dive. Someone has to eat all that fish soup! The marine life here is truly amazing. But diving is often affected by strong currents. Especially after the new moon.

Labroides dimidiatus, Common Cleanerfish

Gymnothorax javanicus Giant Moray

More information about the fish of the Red Sea in the new book: Red Sea Marine Life (Amazon paperback)

All formats and marketplaces (Apple, Google, Gumroad)

Amazing crustaceans – Shrimp living with Worm

The beauty and the Beast? World of crustaceans is extremely diverse! Did you know that some Snapping Shrimps can share burrows with Spoon Worms? Alpheus barbatus is one of the most beautiful shrimps. It is a facultative associate with rock-dwelling echiuran (Ikedosoma cf. elegans here)

I found this couple under a rock on the coast of New Caledonia. This was during a marine biological expedition of the Paris Museum of Natural History. I was struck by the beauty of the shrimp. Why be such a beautiful crustacean? Living under a rock with a worm 🙂

You will find more interesting facts and excellent underwater photos in the Coral Reef Crustaceans book. https://reefidbooks.com/shrimps-crabs/

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.