Deep sea jellyfish (Periphylla periphylla) juvenile, Trondheimsfjord, Norway, Atlantic ocean
RF- Western clownfish (Amphiprion oceallaris) in Magnificent sea anemone (Heteractis magnifica). Raja Ampat, West Papua, Indonesia
Aggregation of Golden jellyfish (Mastigias sp.) in a marine lake in Palau, the golden colour of this species comes from symbiotic algae in its tissues
Portuguese man o war (Physalia physalis) Tenerife, Canary Islands
Gorgonian sea fans (Acalycigorgia sp) on coral reef at Raja Ampat, West Papua, Indonesia
Red sea fan (Melithaea sp.) is surrounded by Glassfish ( Apogon sp.) on a coral reef. Daram Islands, Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean
Wave breaking over the reef, Table coral (Acropora) Safaga, Egypt, Red Sea
Compass jellyfish (Chrysaora hysoscella) with sunburst close to the surface, Cornwall, UK, .English Channel
Blue dragon seaslug (Glaucus atlanticus) with Blue button hydroid colony (Porpita porpita) on which it feeds. Tenerife, Canary Islands. October
Diver approaches a large colony of Elkhorn coral (Acropora palmata) growing in shallow water on a coral reef. Wreck of the Glamis, East End, Grand Cayman, Cayman Islands, British West Indies
Deepsea jellyfish (Periphylla periphylla) juvenile, , Trondheims fjord, Norway, Atlantic ocean
Hard coral (Porites lutea) with Christmas-tree worms (Spirobranchus giganteus), New Caledonia, Pacific Ocean
Blue sea slug (Glaucus atlanticus) that was washed ashore with a mass, multi-day stranding of thousands of Indo-Pacific Portuguese man-of-war (Physalia utriculus)
Moon jelly (Aurelia aurita) drifts over a coral reef. East End, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea
Jellyfish (Pelagia noctiluca) amongst plankton, Shetland Isles, Scotland
Sugar kelp (Saccharina latissima) and Sea anemones (Actiniaria) on rock near iceberg. Tasiilaq, East Greenland. April
Deep sea jellyfish (Periphylla periphylla), Trondheimsfjord, Norway, July
Coral (Euphyllia ancora) polyps brown and green. Lembeh Strait, North Sulawesi, Indonesia
Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles
Anemone prawn (Periclimenes sagittifer) on Snakelocks anemone (Anemonia viridis) Jersey, British Channel Islands, June
Gorgonian / Sea whip coral (Ellisella ceratophyta) with Ring tailed cardinalfish (Apogon aureus) swimming in front, West Papua, Indonesia
Kaleidoscopic image of soft corals (Dendronephthya sp). Egypt, Red Sea
Coral reef with soft corals (Dendronephthya sp. ), encrusting sponges and Pygmy sweepersCoral reef with soft corals (Dendronephthya sp.), encrusting sponges and Pygmy sweepers (Parapriacanthus ransonetti) Similan Islands, Andaman Sea, Thailand
RF - Soft coral (Dendronephthya sp. ) growing on sea bed. West Papua, IndonesiaRF - Soft coral (Dendronephthya sp.) growing on sea bed. West Papua, Indonesia
Lions mane jellyfish (Cyanea capillata) swept in current over a bed of eel grass, along the Eastern shore of Nova Scotia, Canada, July
Three spot damselfish (Dascyllus trimaculatus) with Sea anemone home, Yap, Micronesia
Common anemonefish (Amphiprion perideraion) with eggs in Magnificent sea anemone (Heteractis magnifica) Yap, Micronesia
Flower tree soft corals (Umbellulifera sp. ), Triton Bay, near Kaimana, West PapuaFlower tree soft corals (Umbellulifera sp.), Triton Bay, near Kaimana, West Papua, Indonesia
Green hydra (Hydra viridissima) found in a garden pond. Derbyshire, UK. September. Winner of the Hidden Britain Category of the British Wildlife Photographer of the Year Awards (BWPA) Competition 2017
Lions mane jellyfish (Cyanea capillata) with feeding tentacles spread swimming in the sun in shallow water. Gulen, Norway. North East Atlantic Ocean
Shallow coral reef flat with corals (Pocillopora damicornis, Acropora humilis and Pocillopora verrucosa) in evening light. Gordon Reef, Strait of Tiran, Sinai, Egypt. Gulf of Aqaba, Red Sea
RF - A vibrant Red Sea coral reef scene, with orange female Scalefin anthias fish (Pseudanthias squamipinnis) teeming over Fire coral (Millepora dichotoma)
Oman anemonefish / clownfish (Amphiprion omanensis) in a a Bulb-tentacle sea anemone (Entacmaea quadricolor), coast of Dhofar and Hallaniyat islands, Oman. Arabian Sea
Luminescent jellyfish / Mauve stinger (Pelagia noctiluca) in open water, Gozo Island, Malta. Mediterranean Sea
Portuguese Man-of-War (Physalia physalis) close up of tentacles, Sargasso Sea, Bermuda
Red Sea anemonefish (Amphiprion bicinctus) in their home, a Sea anemone (Heteractis magnifica), on a coral reef. Big Brother island, Red Sea. Egypt
Thimble jellyfish (Linuche unguiculata) aggregation, My Paradise Reef, Cabilao Island, Bohol, Central Visayas, Philippines, Pacific Ocean
Three False clownfish (Amphiprion ocellaris) in Sea anemone (Heteractis magnifica) Lighthouse Reef, Cabilao Island, Bohol, Central Visayas, Philippines, Pacific Ocean
Man-of-war fish (Nomeus gronovi) living within deadly tentacles of Portuguese man o war (Physalia physalis), to whose toxin it is ten times more resistant than other fish, at sea surface. Dominica
Crystal jellyfish (Aequorea victoria) in deep water, Trondheimsfjord, Norway, Atlantic Ocean
Helmet jellyfish (Periphylla periphylla) drifting in the deep sea, Trondheimsfjord, Norway, Atlantic Ocean
Leather corals (Sarcophyton sp. ) fluoresce at night under blue light on a coral reefLeather corals (Sarcophyton sp.) fluoresce at night under blue light on a coral reef. Laamu Atoll, Maldives. Indian Ocean
Portuguese man o war (Physalia physalis) Tenerife, Canary Islands. January
Red sea fan (Paramuricea clavata) with gorgonian corals and Light-bulb sea squirt (Clavelina lepadiformis) Punta Carena, Capri Island, Sorrentine Peninsula, Italy, Tyrrhenian Sea, Mediterranean
Crinoid or feather star (Antedon mediterranea) on Violescent sea whip or Red sea fan (Paramuricea clavata) Punta Campanella Marine Protected Area, Amalfi Coast, Italy, Tyrrhenian Sea, Mediterranean
Sea anemone (Calliactis parasitica) usually associated with hermit crabs, here on a Mediterranean bonnet shell (Semicassis granulata), Ponza island, Italy, Tyrrhenian Sea, Mediterranean
Orange and white soft corals, Dead mans fingers (Alcyonium digitatum) thriving beneath kelp (Laminaria hyperborea). St Abbs, Eyemouth, Berwickshire, Scotland, United Kingdom. North Sea
RF - Caribbean reef sharks (Carcharhinus perezi) swim over a coral reef with Common sea fans (Gorgonia ventalina) and Sea plumes (Pseudopterogorgia sp)
