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[Big Fishes] [School] [Macro] [Endemic species] [Land creatures]
■Scientific name：Crenavolva tigrisWatch video here. Those found off the Similan Islands aree mostly around 1cm long. Seen around the Similan Islands off Koh Bon, Koh Tachai and Richelieu Rock.
■Scientific name：Rhinomuraena quaesitaWatch video here. Found over rocky fragments in deep depths exposed to some current. When young they are black and all male but as they grow they turn blue. They turn into females once they've grown even more and their bodies become yellow. At 0.5m - 1.5m long,they're found around Island 9 of the Similan Islands.
■Scientific name：Rhynchocinetes durbanensisWatch video here. Main features are the white lines on its red body. Also known as cleaner shrimps, they'll clean your hands if you put them in front of them. During night diving they are easy to spot because their eyes shine orange when torches are held over them. Found off the Similan Islands, Koh Bon, Koh Tachai and Richelieu Rock.
■Scientific name：Hymenocera pictaWatch video here. Distinguished from other shimps with brown markings and a blue outline. Likes blue sea stars and skilfully peels away the skin to eat the internal organs. It's 1-2.5cm long and found at Elephant Head Rock and Richelieu Rock.
■Scientific name：Sepia pharaonisWatch video here. Courtship behaviour can be observed off the Similan Islands between December and February. Acts menacingly when divers approach. It's 20-50cm long and found at Richelieu Rock.
■Scientific name：Octopus aeginaWatch video here. Often found over piles of rock and coral in shallow waters of the Similan Islands. It's 30-50cm long,and found off the Similan Islands, Koh Bon and Koh Tachai.
■Scientific name：Panulirus versicolorWatch video here. Large numbers are often seen on night dives off Donald Duck Bay in the Similan Islands. It's 30-50cm long, and found off the Similan Islands, Koh Bon, Koh Tachai and Richelieu Rock.
■Scientific name：Odontodactylus scyllarusWatch video here. Can be seen sticking its head out of its nest but please don't touch it,as its scissor-like blow is very powerful and can crush shells and crabs into pieces. At 5-15cm long,it's found off the Similan Islands, Koh Bon and Richelieu Rock.
■Scientific name：Myrichthys colubrinusWatch video here. Looks like the extremely poisonous Black-Headed Sea Snake but doesn't contain poison.Sometimes approaches lights from boats at night. It's 0.7 - 1.0m long and found off the Similan Islands and Koh Bon.
■Scientific name：Ovula ovumWatch video here. Gets its name because it looks like a chicken's egg. In Japan, it apparently protected the egg once it had been taken from the chicken. It's 5-10cm long, and found off the Similan Islands, Koh Bon and Koh Tachai.
■Scientific name：Stenopus hispidusWatch video here. Because this species is a cleaner shrimp, its main features are its red and white colour that make it stand out. Lives behind rocks during the day and sticks its head out above the rocks at night.
■Scientific name：Etisus splendidusWatch video here. Like the lobsters often seen on night dives, this crab is also very impressive, with huge claws and a bright red shell that looks as though it's been boiled.
■Scientific name：Gymnothorax javanicusWatch video here. With black specks on its brown body,it looks as though it's poisonous. It won't secrete poison if it bites but can cause food poisoning if eaten. In English it's called a Giant Moray and grows up to around 3m.
■Scientific name：Neopetrolisthes maculatusWatch video here. Although shaped like a crab, it's actually a member of the shrimp family and can be distinguished by its number of legs. Lives behind Giant Carpet Anemones and appears in the mornings and evenings to feed.
■Scientific name：Hexabranchus sanguineusWatch video here. Gets its name because its large size and beautiful way of dancing make it look like a Spanish dancer. Quite large among nudibranch species, with a body length of 20-40cm. Found around the Similan Islands.
■Scientific name：Helmut DebeliusWatch video here. This blue-black species that's like a sponge is a member of the shellfish family. It's 5-10cm long and found in gaps between rocks off the Similan Islands and Koh Bon.
■Scientific name：Gymnodoris albaWatch video here. Has red specks over its clear, transparent body. Often seen in pairs chasing one another. Easy to observe because of its large size. Often spotted in coral reefs off the Similan Islands, as well as sandy patches in rocky reefs.
■Scientific name：Trapezia rufopunctataWatch video here. About 1-2cm and lives between the branches of coral such as cauliflower or staghorn coral. Very beautiful with numerous small red specks and a pale, cream body. The red specks on the shell can number 200 on adults.
■Scientific name：-Watch video here. Among the larger of nudibranch species with black lines on a yellow body. Off the Similan Islands it often hides as if to camouflage against the piles of rocks and coral. Found in comparatively shallow areas above 15m.
■Scientific name：-Watch video here. Has black vertical lines over its white body. Found on all coral reefs and rocky areas of the Similan Islands.
■Scientific name：Diadema setosumWatch video here. A spiny species found in all seas. Nocturnal and hides in gaps between the rocks during the day. Emerges at night. Impossible to see many in the Similan Islands but around Thailand and Koh Tao off the Gulf of Thailand, they form groups on the sand.
■Scientific name：Pocillopora eydouxiWatch video here. Groups look like cauliflower but their form can change remarkably because of wave strength, amount of light, breeding grounds and conditions. Come in various colours including brown,light purple, red, pink, green and yellow. Distributed across large areas and live in various environments.Huge number of different kinds.
■Scientific name：Gymnothorax fimbriatusWatch video here. Has a longer mouth and body compared to other eels. Real colour appears to be cream but can look yellow because of a mucous membrane.
■Scientific name：Phidiana indicaWatch video here. Covered in various bright colours including red, blue and yellow. Because it's small it's hard to find but its beauty makes it worth looking for. Often found in rocky areas with similar colours.
■Scientific name：Cadlinella ornatissimaWatch video here. A beautiful nudibranch that has white protrusions with pink tips on its yellow body. There aren't many off the Similan Islands but it definitely exists there.
■Scientific name：Gymnodoris rubropapillosaWatch video here. Beautiful nudibranch with orange spots on its clear transparent body.Contrary to its appearance, it catches and eats other nudibranchs. Found off all dive sites off the Similan Islands but their numbers are low.
■Scientific name：Glossodoris atomarginata Watch video here. Generally cream, blue or black. Mainly eats sponges. Said to change colour depending on the sponge it eats.
■Scientific name：Echinophyllia asperaWatch video here. Forms groups that look like fully-grown cabbage. On the surface are bits of coral that protrude like warts, forming irregular concentric circles.
■Scientific name：Halgerda batangasWatch video here. Has yellow specks that seem stuck to its semi-transparent body. Gets its Japanese name because at first glance it looks like Konpeito, a type of Japanese hard, round candy.
■Scientific name：Echidna nebulosaWatch video here. Has yellow and black patches and likes gaps between rocks. Hard to find because it blends into its surroundings. Males and females are distinguished from the differences in their teeth. An adult male's teeth look like dog's teeth but the females have molar teeth.
■Scientific name：Reticulidia halgerdaWatch video here. Has black specks over its yellow body.
■Scientific name：Risbecia tryonWatch video here. Used to be called a Cheetah nudibranch but its name changed to Risbecia Tryon. Found in all areas off the Similan Islands and seen in pairs chasing one another.
■Scientific name：Glossodoris cinicta Watch video here. Has a yellowish brown body and is covered in brown patches. Its edges can be red, white or yellow. As per the Japanese word monja of monja-yaki (savory pancake), this species gets its Japanese name because it's a mix of different colours.
■Scientific name：-Watch video here. Colour ranges between semi-transparent yellow and brown. Body is covered in white dots and a pattern of lines that looks like a spider's web The points where the lines meet protrude greatly. The lines can be yellow, orange or red, often with a thin, brown border. Some are a bit thick. The thickness of the lines differs depending on species.
■Scientific name：Pteraeolididae ianthinaWatch video here. Got its name because it seems covered in purple bits.Eats species such as jellyfish and takes in the poison to protect itself. Also hosts zooxanthellae and produces its beautiful purple colour through photosynthesis.
■Scientific name：Acanthaster planci（Crown-of-thorns starfish）Watch video here. Feeds on coral.Its numbers greatly impact coral reef ecosystems. It climbs on top of the coral,reverses its stomach and covers the coral surface to absorb and digest the soft bits. Its spines contain poison. If you're accidentally stung, the affected area will swell. Said to cause anaphylactic shock so please be careful when handling them, for example removing them from the reefs. Coral reefs off Okinawa have been dying recently because of this species.
■Scientific name：Periclimenes platychelesWatch video here. This species is transparent and its legs can be difficult to find. Its limbs with pincers are very long and strong but hard to see because they're transparent. Easier to spot if you focus on the orange on the fingers and lemon yellow colour of the joints. You can often see through its stomach to the intestines. Gets its name from the vivid orange on the fingers.
■Scientific name：Chromodoris kunieiWatch video here. Has blue specks on its yellow body. Relatively easy to find in the Similan Islands, usually over rocky areas or coral reefs.
■Scientific name：Halgerda willeyiWatch video here. Has a semi-transparent body with black and orange lines. Doesn't look like a pineapple but is known as the Pineapple Nudibranch (Halgerda willeyi).
■Scientific name：Gymnothorax thyrsoideusWatch video here. Relatively small, and gets its Japanese name from a rusty tinge on its body.Lives in rocky caverns and feeds on cephalopods such as octopus and crustaceans as well as small fish.
■Scientific name：Hypselodoris apolegmaWatch video here. Said to be the most beautiful of nudibranch species. Extremely attractive with its purple body. Very few off the Similan Islands but it has been seen on the rocks at Deep Six.
■Scientific name：Lysmata amboinensisWatch video here. Its yellow body and red and white lines stand out a lot. Also has quite long white whiskers. Known as a Cleaner Shrimp, it lives with other fish and cleans them. Popular among divers and known to clean divers' hands sometimes.
■Scientific name：Glossodoris pallidasWatch video here. Aren't many off the Similan Islands but are known to exist in each area.
■Scientific name：Phyllidiopsis striataWatch video here. Body is egg-like and there are three blue-white lines along its back. The line in the centre is slightly short. On each side of the lines are 4 black lines. The back is semi-transparent and blueish-white. There are also small white protrusions like warts.
■Scientific name：Saron spWatch video here. Rich in colour and popular with divers. Also called Saron Shrimp. Found during night dives and hides in gaps between the rocks during the day.
■Scientific name：Phyllidia coelestisWatch video here. Standard type of Phyllidiidae nudibranch. Several types look similar. Yellow colour stands out a lot against rocky slopes so they're easy to find.
■Scientific name：Dichrometra flagellataWatch video here. Found all over the world and often seen stuck to the top of rocks. They can easily stick to wetsuits as well so beginner divers or those who aren't good at neutral buoyancy sometimes find that they've taken one without knowing. Gently touch the area of rock it's sticking to with a stick or something, and watch it open and spread out.
■Scientific name：AlcyonaceaWatch video here. Forms groups of about 10-50cm high, where many polyps with eight tentacles gather. Has no calcium carbonate bony axis. It's soft and fleshy with a leathery surface. Its slime smells bad. Groups can be rod-like, finger-like, mushroom-like or willow-like. Some look like typical coral and are popular among divers.Groups come in various of colours from red to yellow.
■Scientific name：Anthogorgia bockiWatch video here. Stretches out as if to obstruct the current, and uses its mesh-like form to catch nutrients drifting by. Those that had broken off and sunk to 30-40m after the tsunami were collected and found to be surprisingly heavy.Today, they are found at every dive site.
■Scientific name：Gymnomuraena zebraWatch video here. Gets its name because it looks like a giraffe with its black body and cream-coloured lines. Rare kind of moray eel that's distinguished by its special teeth that it uses to crunch up species like shells. It's both male and female.
■Scientific name：Linckia laevigataWatch video here. Diameter:20-25cm, Surface colour:Blue Number of Arms: 5.Arms can reach over 10cm long. Unlike other starfish, they have rounded tips. Blue species are often spotted but some can be green or brown. Sometimes eaten by Harlequin Shrimps. Found from the Similan Islands to Richelieu Rock.
■Scientific name：Mastigias papuaWatch video here. Small jellyfish with no poison. Around its mouth are eight tentacles. Gets its Japanese name because it has the same number of tentacles as the octopus. Often seen drifting past in the current. Found between the Similan Islands and Richelieu Rock.
■Scientific name：Urocaridella sp.3Watch video here. Has deep purple and yellow specks over its transparent body. There are yellow lines on its pincers, belly and tail. Lives in small groups,deep in the holes of bommies on sandy areas. Several are seen cleaning one fish together.Found between the Similan Islands and Richelieu Rock.
■Scientific name：Urocaridella spWatch video here. Seen in relatively dark areas like rocky caverns or cave entrances. Quite a large species in this family and can be seen cleaning big moray eels or groupers. Transparent, with auburn specks, and is found off the Similan Islands and Richelieu Rock.
■Scientific name：Octpus cyaneaWatch video here. Blends in with the rocks. When in pairs, acts menacingly towards divers. Found from the Similan Islands to Richelieu Rock.
■Scientific name：Spirobranchus giganteusWatch video here. Lives above porites or rocks in coral reefs or rocky areas.Type of Bristle Worm. It's 5-7cm long and its umbrella-like structure that looks like a Christmas tree developed as gills (for respiration). It's called Saikan, or crown, in Japanese. When stimulated, it quickly withdraws its crown from view. Comes in various colours from red, blue and yellow to green. Found between the Similan Islands and Richelieu Rock.
■Scientific name：Camposcia retusaWatch video here. As its Japanese name suggests, this crab is a master of camouflage as it sticks to algae or bits of rubbish. Also decorates itself by sticking seaweed, sponges or bits of shell to its needle-like hair. Nocturnal and seen during night dives as it hides in rocky crevices during the day. Found between the Similan Islands and Koh Tachai.
