Marine Life in the Red Sea: Identifying Fish, Invertebrates…
22 January 2015
For an enlargement click the photo.
Blue Spotted Stingray, Taeniura lymma
The Dasyatidae family contains about 100 species, one of which is the Blue Spotted Stingray. Like all stingrays they have venomous spines at the base of the tail. They breathe by drawing water through a small hole behind the eye and expelling it through gill slits on their undersides. They often lie on sandy bottoms, flicking sand over themselves as camouflage. They feed on molluscs and crabs. Common and easy-to-spot throughout the Indian and Pacific Oceans, including the Red Sea and the Great Barrier Reef. Simple to identify with their oval shape and blue spots. Not aggressive, but if you accidentally step on one the spine may be driven into your leg. This causes intense pain, increasing for around 90 minutes and lasting, if untreated, for 1 to 2 days. More on Stingray…
Tassled Scorpionfish, Scorpaenopsis oxycephala
The scorpionfish is one of the most venomous fish in the world. It has several spines linked to venom glands. The poison causes severe pain and paralysis. The scorpionfish is extermely well-camouflaged. It can change colour to match its background and has many "tassles" masking its outline. This Tassled Scorpionfish lives from 1 to at least 35 m in the Red Sea and Indo-Pacific. Lacking a swim bladder, it remains on or near the bottom. Lethargically, the fish waits for prey to pass by then opens its lower jaw and sucks its victim in. Not many animals prey on the scorpionfish, its venom deterring most. A fully grown octopus though does not seem to be affected by the spines and will envelop and eat the scorpionfish. More on Scorpionfish…
Giant Moray Eel, Gymnothorax javanicus
The largest of the moray eels, growing up to 3 m. Quite common and always interesting to observe. Feeds primarily on fish, occasionally on crustaceans and octopus. Morays live in holes and generally hunt by night. You may see them rhythmically opening and closing their mouths. They do this to maintain a respiratory current past the gills. Morays undergo a sex change during growth, changing from male to female. More on Giant Moray…
Geometric / Grey / Snowflake Moray Eel, Sidera grisea
The Geometric moray has a long body with one continuous fin along its back. Like other morays it has elongated nostrils. You can easily recognise it by the dashed lines patterning its face, as shown in our photo. The Geometric moray is the most common eel in the Red Sea. Quite small for a moray, the Geometric moray reaches 65 cm long. It lives at depths down to 40 m on coral and rocky reefs. You may see groups of up to 10 young eels sheltering in rock crevices. The black dashes on the face and body of this moray mark its pores. These are part of its lateral line system which detects changes in pressure and so can be used to detect movement and vibration in the surrounding water. More on Sidera grisea…
Carpet Flathead Fish (Crocodilefish), Papiloculiceps longiceps
Mainly lives on sand and rubble near coral heads, although you might also find it in patches of seagrass. It stays shallow: between 1 and 15 m. The flatheads are flattened fishes. They have two dorsal fins and bony ridges and spines on their heads. The body is mottled above, whitish below. The Carpet Flathead grows to 70 cm. It is a very placid fish which, confident in its camouflage, lets you approach closely. Although related to scorpion fish it is harmless. More on Crocodile fish…
Lionfish (Turkeyfish), Pterois miles
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
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….
Coral Grouper (Coral Rock-Cod), Cephalopholis miniata
Found around coral in areas with clear water. Easy to spot and fairly common. Range from 2 to 150 m and feed mostly on fish. Juveniles have yellow bodies with blue spots and as adults grow to around 41 cm. Like all groupers, Cephalopholis miniata has a large mouth and sharp teeth. They use grinding plates within their throats to break up prey. Groupers are the most important family of reef based predators. Territorial and solitary apart from in the mating season in June. Also common in other parts of the world, including Australia. More on Grouper…
Lyretail Anthias, Pseudanthias squamipinnis
Also known as a Jewel Fairy Basslet, this are the most common species of Anthias found in the Red Sea. The male and female are different colours. The bright orange, smaller fish are the females; pinky-yellow coloured fish the males. You see them in large groups clustered around coral outcrops. All fish start off life as females. Where a male is lacking, the dominant female fish will turn into a male. The males are territorial and keep a harem of female fish. More on Lyretail Anthias…
Picasso Trigger Fish, Rhinecanthus assasi
Trigger fishes are so called because of the shark-fin shaped trigger they are able to raise in defence. They use this to jam themselves into a crevice in the coral. The trigger is actually the first spine of its dorsal (top) fin. They bend the second spine forward to fix the first firmly in position. When the fish is swimming the fin is flattened into a groove. More on picasso fish….
Masked Puffer, Arothron diadematus
Distinctive looking, this small pufferfish has a black mask over its eyes reaching back to its pectoral fins, and a black mouth. It is common on fringing coral reefs in the Red Sea. Elsewhere it is replaced by Arothron nigropunctatus (the Blackspotted Puffer). However, some experts believe these to be the same species. 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. The fish aquire the bacteria by grazing on the reef and eating molluscs and other invertebrates. 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. More on Masked Puffer…
Sabre or Long-Jawed Squirrelfish, Sargocentron spiniferum
This species is the largest of the squirrelfish. It's common in the Red Sea at all depths likely to be dived, and feeds primarily on crabs. A member of the Holocentridae family, squirrelfish have large eyes and are nocturnal. During the day you'll find them under ledges and in caves, away from the light. Growing up to 45 cm, they live alone or in small groups. You can distinguish Sargocentron spiniferum from other squirrel fish by the red blotch behind its eye. Like many nocturnal fish, Sargocentron spiniferum is red. To us it is easy to spot during the day, but to other fish it blends into its dark crevice or cave. Long red light wavelengths don't penetrate water well, so fish colour vision tends to be tuned to the shorter, blue and ultra-violet, end of the spectrum. This means that red and pink fish are inconspicuous. More on Squirrelfish…
Hawkfish, Paracirrhites forsteri
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 hawkfish….
Pygmy Sweepers, Parapriacanthus ransonneti
Also known as glassfish and golden sweepers, you find dense schools of these small fish throughout the Indo-Pacific, from the Red Sea to Australia. They like shady places during the day: wrecks, overhangs and caves. At night they venture out to feed on zooplankton. More on Pygmy Sweepers…
Crown Butterfly Fish, Chaetodon paucifasciatus
Can be seen between 4 and 30 m in pairs or groups. It's key identification feature, though, is the yellow stripe through the eye. It also has a distinctive red rear. The Crown Butterfly fish feeds on coral polyps, algae and crustaceans. It is only found in the Red Sea and the Gulf of Aden. More on Crown Butterfly fish….
Masked Butterfly Fish, Chaetodon semilarvatus
Live around coral, from 3 to 20 m. Very common throughout the Red Sea. Around 23 cm long, the Masked butterfly fish is large for its family. You generally see them in pairs or large groups. More on Masked Butterfly Fish….
Emperor Angelfish, Pomacanthus imperator
Emperor Angelfish have deep, flat, bodies and small mouths. They are striking to look at, being large (40 cm) and colourful. The flattened shape of angelfish enable them to wind their way amongst the corals; it also enables them to retain their stability when manoeuvring at low speed to pick up items of food, in the same way that a keel of a sailing boat helps with its steering and prevents it from turning over. The young angelfish looks totally different to the adult, having concentric white rings on a dark blue background. You will find the juveniles under ledges or in holes of shallow reef flats. Adults go deeper, from 3 - 70 metres. Adult males typically defend a large territory containing 2 females. However, you ususally see the fish in pairs. The fish are protogynous. This means that they are born as females and develop into males later.More on Emperor Angelfish….
Bluefin Trevally, Chaetodon semilarvatus
Trevallys are large silvery fishes with forked tails. They are fast-swiming predators of the waters above the reef and in the open sea. The Bluefin Trevally is distinctively coloured, being the only trevally with electric blue fins and blue speckles on a gold or green background. This fish can be as large as 1 metre, but you normally see individuals smaller than this. They range from the shallows to the depths, usually singly but you may see a trevally small school. More on Bluefin Trevally….
Blackspotted Sweetlips or Grunts, Plectorhinchus gaterinus
Sweetlips have thick lips, continuous dorsal fins and truncate or emarginate tails. Adults are often inactive during the day and shelter near or under ledges. They feed at night on bottom-dwelling invertebrates. The juveniles of Blackspotted sweetlips have 6 black lines on their heads and bodies, these become spots with age. More on Sweetlips…
Soft coral, Dendronephyta species
The body of this soft coral, Alcyonacea order, is stiffened with yellow spicules. Here the individual polyps are open, showing their 8 tentacles (the 8 tentacles help to confirm identification). It is partly down to these that much of the diving in the Red Sea is so beautiful. More on Soft Coral…
Soft coral, Dendronephthya hemprichi
This species 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. More on Dendronephthya hemprichi…
Fire corals are so called because of their powerful stinging hairs or nematocysts. These are used primarily for defence against fish like parrotfish which would otherwise nibble the coral. However, they are strong enough to injure divers who brush their skin against them, causing burning and itching. If this happens rinse with seawater and apply vinegar or methylated alcohol on the affected area. In a severe case anti-histamines can help, but seek medical advice. More on fire coral…
Cup Coral, Tubastraea aurea
Tubastraea lack symbiotic algae and do not contribute to reef building. They tend to grow on underhangs, drop-offs and reef slopes in strong currents. The name combmes from the Latin for tube (tubus) and the Greek for star (sastron). At night the coral skeleton (corallum) is hidden by a ring of bright yellow tentacles, as shown in the photo above. During the day the tentacles are retracted into deep circular calices. The skeletal tubes measure 5-15 mm across and protrude by 10 mm or more from the coral surface. Cup coral is also known as sun coral.More on cup coral…
Table Coral, Acropora
Acropora corals are distinctive - no other corals resemble their complex branching structure, which provides ideal habitat for many coral reef organisms. Acropora species appear to be among the fastest growing corals, with upward growth between 10 and 20 cm per year. Acropora is usually branched, except when young, but the size and shape of the branches vay according to the species. More on table coral…
Feather Star, Lamprometra species
Feather stars, or crinoids, are so called because their arms look just like feathers. By day they keep curled up but on night-dives you see these pretty animals in their warm colours, with their feathery arms extended. When food is plentiful, with strong currents carrying large amounts of plankton, feather stars will form large groups. They appear to have no particular predators. Look closely and you will often see another animal - such as a shrimp, crab or fish - living with the feather star. More on Featherstars…
Polyclad Flatworm, Pseudoceros sp
Flatworms look very similar to nudibranchs: they are beautifully coloured, the same shape and may move similarly by muscular propulsion. However, they have thinner bodies than nudibranchs and also move by beating hair-like cilia on their undersides - rippling through the water. More on flatworm….
Yellow Lip Shield Slug, Chelidonura flavolobata
Just few centimeters long, this is a kind of nudibranch which looks dark red in natural light or dark blue if you shine a torch on it. It has two yellow head lobes which look just like sticky-out eyes. Only found in the Red Sea. Common names include Red Sea Chelidonura and Yellow Lip Shield Slug. Part of the Aglajiidae familiy.
Cuttlefish, Sepia species
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 aboveL 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. More on Cuttlefish page….
The octopus is solitary. Mating can be risky for the male: he is smaller than the female and risks being attacked. The female watches his body postures and skin pattern. Once accepted the male stretches out a modified arm towards the female - shown in our photo. The arm has grooves along which sperm passes to the female's mantle cavity. See our Octopus page for more details.
Hermit crab, Dardanus species
Hermit crabs scuttle about the sea-floor using someone else's shell for a home. They always use empty shells and never kill the original occupant. Some of the Dardanas species of Hermit crab stick sea anemones on their shells. This camoflauges the crab and the stinging cells of the anemone may protect the crab from predators such as octopus.See our Hermit crab page for more details. More on Hermit Crabs
Green Turtle, Chelonia mydas
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 their body fat. 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….
By Jill Studholme,
- Coral Reef Guide Red Sea
- by Ewald Lieske and Robert Myers, Collins, 384 Pages, Paperback (2004)
Coral Reef Guide Red Sea covers all common species of underwater life of the Red Sea and the Gulf of Aden, you are likely to see while diving or snorkelling. Each species is illustrated with a full-colour photograph and the text gives details of range and characteristic behaviour. A map of good dive sites appears on the inside front cover. Includes jellyfish, corals, nudibranchs, starfish, sea urchins, fishes and turtles. An excellent sea life guide which I always take to the Red Sea
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