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Marine Life - The Creatures of the Month

17 April 2024
For the first time in one place - the highlights of our Creature of the Month series published in SCUBA News. For more information and indentification notes click a photo.

You can search for more Creatures of the Month on our news site.

Mammals Turtles Fish Coral Jellyfish & Anemones Sponges Cephalopods Nudibranchs

Marine Mammals

There are four groups of marine mammals: cetaceans which are the whales, dolphins and porpoises; pinnipeds which are seals, sea lions and walruses, sirenians which are the dugongs and mannatees and the fissipeds which include polar bears and sea otters.

Grey Seal | Dugong

Grey Seal, Halichoerus grypus

Grey Seal
Photo credit Tim Nicholson, taken in the Isle of Man.

Found in: North Atlantic especially Britain.

Grey seals live in the North Atlantic Ocean. Half of the world's population are found on and around British coasts, and numbers here have doubled since 1960. However, the northeast Atlantic population as a whole (from Portugal to Norway and Iceland) is considered to be Endangered. Their lifespan generally ranges from fifteen to twenty-five years, but the oldest recorded living grey seal is 46 years old.
More on Grey Seals....

Dugong, Dugong dugon

Photo credit Suzanne Challoner, taken in the Red Sea.

Named from the Malay for "Lady of the Sea", Dugongs are said to have inspired the legends of mermaids.

They can eat as much as 40 kg (88 lb) of seagrass a day, leaving distinctive troughs in seagrass meadows. They live a long time: the oldest dugong yet found was estimated to be over 70 years old. Dugongs have dense, massive bones, which help to keep them submerged. Their lungs lie along their back and act like floats, keeping them horizontal in the water. They are the only representatives left in their family Dugongidae.
More on Dugongs....


Seven species of turtle live in our seas. Six of these are threatened with extinction, and there isn't enough known about the other to decide.

Green Turtle

Green Turtle, Chelonia mydas

Green turtle eating seagrass
Photo credit David Collins, taken in Marsa Alam, Red Sea.

Found in: tropical and subtropical oceans worldwide

Green turtles can live to 23 years old. The age to maturity appears to be the longest for any sea turtle. Green turtles don't look green - they got the name from when they were regularly eaten because their body fat is a greenish colour. A large turtle, individuals can grow to 120 cm. As they age they move to a vegetarian diet, eating sea grass and algae.
More on Green Turtles....


Fish are vertebrates and live in water, other than that they are very different from each other.

Lionfish | Red Sea Clownfish | Freckled Hawkfish | Spadefish | Batfish | Crocodilefish | Tompot Blenny | Leopard-Spotted Goby | Golden Trevally | Great Barracuda | Spotted Snake Eel | Conger Eel | Geometric Moray Eel | Bull Shark | Giant Manta Ray | Sicklefin Devil Ray | Blue Spotted Stingray

Lionfish (Turkeyfish), Pterois miles

Photo credit Tim Nicholson, taken in the Egyptian Red Sea.

Found in: Native from the Red Sea to South Africa and Indonesia. Now found elsewhere as an invasive species.

Found in the Red Sea and Indian Ocean to the Andaman Sea. Elsewhere replaced by the very similar P. volitans. Usually 11 dorsal rays (those on the top of the fish). A sting from this fish can be very painful, and possibly fatal. They often shelter under ledges during the day, being more active at dusk and during the night when feed on fishes and crustaceans using their non-stinging pectoral fins to shepherd prey into their mouths. The Lionfish's poisonous spines allow it to be conspicuously coloured, warning predators to keep their distance.
More on Lionfish...

Red Sea Clownfish, Amphiprion bicinctus

Amphiprion bicinctus
Red Sea Clownfish in Bubble Anemone

Found in: Red Sea

The most common clownfish in the Red Sea, hence its name. But it doesn't just live in the Red Sea. You will also find it in the Gulf of Aden and in the Chagos Islands in the Pacific some 3364 km away. But curiously nowhere in between. Clownfish start off male, but if the female dies the dominant male will change into a female. The Red Sea Clownfish lives from the shallows down to 30 m, generally living in pairs in association with an anemeone. The tentacles of the anemone protect the clownfish from predators. At first contact with the anenome the clownfish jerks back, but gradually its mucus coating gives it immunity to the anemone's stinging nematocysts.
More on Red Sea Clownfish....


Freckled Hawkfish, Paracirrhites forsteri

Freckled hawkfish
"Waiting for lunch", photo credit Tim Nicholson, taken in the Red Sea

Found in: Indo-Pacific including Red Sea and East Africa

Seen from 1 to 33 m resting motionless on coral. It is carnivorous, feeding on crustaceans and small fish. A member of the Cirrhitidae family, it can change sex. Young fish are all female. One male has a harem of females - if the male dies one of the females changes sex to take its place. Males are very territorial.
More on freckled hawkfish….


Sabre Squirrelfish, Sargocentron spiniferum

Freckled hawkfish
Sabre Squirrelfish, photo credit Tim Nicholson, taken in the Red Sea

Found in: Indo-Pacific including Red Sea and East Africa

The biggest squirrelfish in the world is nocturnal. during the day you’ll find them under ledges and in caves, away from the light.
More on sabre squirrelfish….

Spadefish (also known as Batfish), Platax spp

Longfin spadefish
Longfin spadefish. Vitaliy/Depositphotos

Found in: Indo-Pacific including Red Sea

These slow moving fish are not at all intimidated by divers, and often come to greet you on your dive - where to see them and why some of them follow turtles.
More on Spadefish....

Crocodilefish or Carpetflathead, Papilloculiceps longiceps

Crocodile fish or Carpetflathead
Photo credit Tim Nicholson, taken in the Red Sea

Found in western Indian Ocean, including Red Sea & Gulf of Aqaba

A very placid fish which, confident in its camouflage, lets you approach closely. Although related to scorpion fish it is harmless.
More on Crocodilefish….

Tompot Blenny, Parablennius gattorugine

Tompot Blenny
Tompot Blenney, photo credit Tim Nicholson, taken in the Isle of Man

Found in: Northeast Atlantic, Mediterranean, Sea of Marmora

This charming little fish, with the expressive face, generally looks as if it is either smiling or puzzled. Unusually small for a blenny, you can see them in temperate waters peering out from crevices in reefs or wrecks.
More on Tompot Blenny….

Leopard-Spotted Goby, Thorogobius ephippiatus

Leopard-spotted goby
Leopard-Spotted Goby, photo credit Christophe Quintin (CC BY-NC 2.0)

Found in: Mediterranean and Eastern Atlantic

A shy fish, Thorogobius ephippiatus lives in cracks on steep walls and caves. Shipwrecks are also a favourite habitat. You find them in the shallows and down to 40 m. It tends to face its crevice home and shoot back in if disturbed, making it difficult to take photos of it face on.
More on Leopard-Spotted Goby….

Ghost Goby, Pleurosicya micheli

Ghost goby in the Canyon, Dahab
Tiny ghost goby in Dahab, Red Sea. JS

Found in: the Indo-Pacific, including the Red Sea

If you look carefully at this semi-translucent little fish you can see its organs. The ghost goby lives mainly on stony corals to around 30 m. Its red fluorescent eyes probably helps them forage for their preferred food of miniscule crustaceans (red fluorescence enhances visual contrast at depths below 10 m).
More on Ghost Goby….

Masked Pufferfish, Gnathanodon speciosus

Masked pufferfish grazing on coral
Masked pufferfish, Red Sea. Jill Studholme

Found in: Red Sea

Distinctive looking, this small pufferfish has a black mask over its eyes and a black mouth. It is common on fringing coral reefs in the Red Sea. They are called pufferfish because when threatened they greatly inflate themselves with water, making themselves look much larger than they usually are. This defence mechanism is important because they move so slowly through the water they would otherwise be easy pickings for predators. Their second line of defence is their toxicity. The Puffer's toxin - tetrodotoxin - is produced within the pufferfish by bacteria. Weight-for-weight, tetrodotoxin is up to 100 times as deadly as the venom of the black widow spider and one of the most poisonous natural substances. Their toxin is used to treat breast cancer.
More on Masked Pufferfish….

Golden Trevally, Gnathanodon speciosus

Juvenile Golden Trevally
Juvenile Golden Trevally with Diver. Photo credit Jill Studholme, Red Sea

Found in: Indo-Pacific

Young Golden Trevally are strikingly coloured, their gold and black striped garb showing from where their name comes. These young fish like to seek out large animals like sharks, groupers and dugongs for protection, acting as pilot fish. Sometimes they make a mistake and decide that a diver is the perfect companion.
More on Golden Trevally….

Great Barracuda, Sphyraena barracuda

Great Barracuda
Photo credit National Park Service

Found in: tropical to warm temperate waters

The Great barracuda is amongst the top predators in their environment and use very highly developed smell and vision senses to locate their prey. When attacking, the barracuda will charge at fast speed (approximately 12 ms-1) and ram their target. They then unleash the power of their jaws which allows them to slice through their prey, even those larger than the barracuda itself.
More on Great Barracuda...

Geometric Moray Eel, Gymnothorax griseus

Geometric Moray
Photo credit: Tim Sheerman-Chase (CC BY 2.0)

Found in: Indo-Pacific

Small with distinctive face patterns which mark the pores that help the eel detect movement and vibration in the surrounding water. This plus four nostrils and speed of movement make the geometric eel such a good hunter that sneaky groupers hang round them and scavenge on the prey the eels flush out of cracks and crevices in the reef.
More on Geometric Moray Eels...

Spotted Snake Eel,Myrichthys maculosis

Spotted Snake Eel hunting
Photo credit Jill Studholme

Found in: Indo-Pacific

When is sea snake not a sea snake? When it's a spotted snake eel. These eels live throughout the Pacific Ocean, from the Red Sea to South Africa and Australia.
More on Spotted Snake Eels...

Conger Eel, Conger conger

Conger Eel
Photo credit Tim Nicholson

Found in: Northeast Atlantic and Mediterranean

Congers breed only once in their lives, at between 5 and 15 years of age. They migrate to deep water to spawn – some sources say as deep as 4000 m – in one or more areas between Gibraltar and the Azores in the mid-Atlantic. After spawning they die, their larvae drifting back into coastal waters.
More on Conger Eels...

Bull Shark, Carcharhinus leucas

Bull Shark
Photo credit Pterantula (CC BY 2.5)

Found in: worldwide tropical and subtropical seas plus rivers and lakes

One of the extraordinary things about bull sharks is that they are as happy in freshwater as they are in the sea. They have even been seen far inland up the Mississippi river. Many spend time in the freshwater Lake Nicaragua – jumping up the river like salmon to get there.
More on Bull Sharks...

Giant Manta Ray, Manta birostris

Manta Ray
Photo credit Tim Nicholson

Found in: worldwide

Awesome to see underwater, the Giant Manta Ray is an enormous fish spanning nearly 7 m (22 feet). They live in warm waters around the world, gracefully flying through the water with steady sweeps of their giant wings.

Sicklefin Devil Ray, Manta birostris

Sicklefin devil rays. Photo credit: Tim Nicholson.

Found in: worldwide but congregate in Azores and the Saint Peter & Saint Paul Archipelago

Sometimes mistaken for manta rays, you can tell these rays apart by their dark green to brown colour. Their "horns" (cephalic fins) point forward rather than curling like the mantas. This is were they got their name "devil ray".

Blue Spotted Stingray, Taeniura lymma

Bluespotted fantail ray
Photo credit: Garry Frazer

Found in:Indo-Pacific

You find this ray on sandy bottom around coral reefs, down to 50 m. They like to lie on the bottom and flick sand over themselves to hide, making it easier for them to prey on molluscs and crabs. For such a commonly seen ray, much about them remains unknown. For instance, nobody knows how long they live (but the lifespan of similar species is around 10 years). They have many names including bluespotted ribbonray, ribbontail stingray, bluespotted fantail ray and blue spotted lagoon ray


Highly intelligent marine molluscs, including octopus, squid and cuttlefish. The name of this group means "head foot", from the Greek. This is because their arms connect to their heads.

Cuttlefish | Octopus

Cuttlefish, Sepia species

Cuttlefish, Sepia sp, taken on Agincourt Reef, Australia
Sepia sp. - Cuttlefish Taken off Agincourt Reef, Australia, by Tim Nicholson.

The cuttlefish has almost incredible powers of mimicry. It can control the colour, patterning and texture of its skin to perfectly match its surroundings. And not just from above, the camouflage works from whichever angle it is observed. From birth, cuttlefish can display at least 13 type of body pattern, made up from over 30 different components.

Blue Ringed Octopus, Hapalochlaena lunulata

Blue Ringed Octopus
Blue Ringed Octopus. Photo credit: Penny Ash

Found in: Northern Australia and Western Pacific.

The blue-ringed octopus – Hapalochlaena lunulata – is said to carry enough venom to kill 26 people. These small animals spend much of their time in hiding, camouflaged. But when disturbed, the octopus will flash around 60 beautifully iridescent blue rings and, when strongly harassed, bite and deliver a neurotoxin in its saliva. Don't pick one up.


Also known as sea slugs, brightly coloured nudibranchs are found throughout the world's seas.

Orange Clubbed Nudibranch | Scarlet Lady Nudibranch | Violet Nudibranch

Orange clubbed nudibranch, Limacia clavigera

Orange clubbed nudibranch, also known as the Yellow-clubbed sea slug. Taken in the Isle of Man. Photo credit: Tim Nicholson, from his excellent book Nudibranchs and Sea-slugs.

Found in: North East Atlantic - Europe

With orangy-yellow "clubs" around its body, curving inwards over its back, this is a delightful nudibranch. Normally up to 20 mm long. The nudibranch's rhinophores, which it uses to smell or taste, are yellow tipped and lamellate or folded.

Scarlet Lady Nudibranch, Coryphella browni

Nudibranch, Coryphella browni, Isle of Man
Coryphella browni taken on Chickens Rock in the Isle of Man. Photo credit: Tim Nicholson.

Found in: Europe

Coryphella browni has a translucent body and numerous red cerata with white tips, on its back. The inner cerata are longer than the outer. It grows up to 5 cm long. You find it around the British Isles and Northern Europe. There are other species very similar to C. browni, such as Coryphella lineata which is distinguished by white lines down its body and along its cerrata.

Violet Nudibranch, Flabellina affinis

Flabellina affinis nudibranch feeding on Eudendrium hydroid by Tim Nicholson
Flabellina affinis taken in the Medes Isles, Spain. Photo credit: Tim Nicholson.

Found in the Mediterranean, on the Atlantic coast of France, Spain and Portugal, and in the Canary Islands. This pretty pink nudibranch grows to 5 cm long and feeds on hydroids. Not just any hydroids but only those in the Eudendrium genus like the ones in the photo.

Coral, Jellyfish and Anemones

Coral, jellyfish and anemones all belong to the cnidarians group of invertebrates

Lion's Mane Jellyfish | Jewel Anemone | Plumose Anemone | Soft Coral

Lion's Mane Jellyfish, Cyanea capillata

Lion's Mane Jellyfish
Lion's Mane Jellyfish, taken in the Isle of Man, by Tim Nicholson.

Found in: Arctic, north Atlantic, north Pacific

With tentacles up to three metres long and covered with stinging cells, it's better not to get too close to the Lion's Mane jellyfish. It's body can be 2 metres across, making it one of the largest species of jellyfish.

Jewel Anemone, Corynactis viridis

jewel anemones, Corynactis viridis
Jewel anemone, taken in the Azores, by Tim Nicholson.

Found in: northeastern Atlantic Ocean and Mediterranean

These flower-like animals, up to 2.5 cm (1 inch) across, prey on invertebrates which they have paralysed with nematocysts and caught with their 100 ball-tipped tentacles. They favour fast-flowing water, so look for them where strong currents occur from shore level down to around 80 m.

Plumose Anemone, Metridium senile

Plumose anemones
Plumose anemone, taken in the Isle of Man, by Tim Nicholson.

You often see Plumose anemones in large numbers when diving in temperate waters. They comprise a tall, smooth column topped with a crown of feathery tentacles.

Soft coral, Dendronephthya hemprichi

Soft coral, Dendronephthya hemprichi
Soft coral, Dendronephthya hemprichi taken by Tim Nicholson on the wreck of the Carnatic in the Red Sea

Found in: Red Sea to Western Pacific

This animal is common in the Red Sea and a pioneer settler. It can clone small fragments of itself with root-like processes that let them quickly attach to artificial structures like wrecks. Especially vertical structures. (Our photo was taken on the wreck of the Carnatic.) One of the Nephtheidae family, the soft coral takes in sea water to expand its body before feeding. This builds up a positive pressure inside the coral that supports the branches and trunk. Unlike most other corals, D. hemprichi don't depend on symbiotic algae: they are azooxanthellate (asymbiotic). Instead they feed almost exclusively on phytoplankton.

Xenid Coral, Xenia umbellata

Xenid coral
Xenid Coral, Xenia umbellata taken by Jill Studholme at Marsa Shona, Red Sea

Found in: Red Sea, Madagascar, South Africa

If you've dived in the Red Sea or Indo-Pacific you will have seen pulsating soft coral repetitively "grabbing" at the water. They are so common that we take them for granted. But only one family of coral does this - the Xeniidae. Even within this family, only a few members pulsate.

Giant Sea Fan, Annella mollis

Giant fan coral
Diver behind giant sea fan. Photo credit: Garry Frazer

Found in: Red Sea to Western Pacific

A gorgonia. Growing at right angles to the prevaling current, their tentacles strain microscopic particles of food from the water. When currents threaten to damage a colony, they can bend and then spring back into their original position. The giant sea fans take 10 to 15 years to reach their maxium size. Sea fans are actually colonies of many small individual polyps connected together to form a lacey sheet.

Red Boring Sponge, Pione vastifica

Red Boring Sponge
Red Boring Sponges on coral reef. Stephan Kerkhofs/Depositphotos

Found in: North Sea, Red Sea, Mediterranean Sea, Black Sea, Caribbean Sea, Atlantic and Pacific, in depths below 10 m.

The fascinating excavating, recycling, anything-but boring, boring sponge. Not always red, you often see them is shades through orange to yellow.



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