Encyclopedia

Gloomy NudibranchTambja Morosa Nearly black at first glance, this nudibranch comes alive with flashes of deep blue scattered across its back and along the mantle edge. Its dark, slightly wrinkled body has a soft, velvety quality, while blue-green and violet tones gather around the rhinophores and feathery gills. The overall effect is moody rather than gloomy, with just enough electric color to keep this shadowy little animal from disappearing completely into the reef. Size: Up to around 70–75 mm Range: Indo-Pacific; from East Africa and the Red Sea through the Philippines, Indonesia and Japan to Australia, New Caledonia, Fiji and...

Willan's ChromodorisChromodoris Willani A rich blue mantle gives this nudibranch an almost electric presence, broken by crisp black lines that sweep around the body and a scatter of tiny dark spots across its back. The rhinophores and feathery gills carry their own pale speckles, while a clean white edge keeps the whole pattern sharply contained. It is a remarkably graphic little animal, with just enough irregularity in the lines to keep it from feeling too perfectly arranged. Size: Up to around 45 mm Range: Indo-West Pacific; from Indonesia and the Philippines through Malaysia, Japan, Vanuatu and other western Pacific islands...

Regal Sea GoddessFelimare Picta Deep blue gives this nudibranch its dramatic presence, while fine yellow lines and spots wander across the back in patterns that become more fragmented toward the edges. A vivid yellow border traces the mantle, echoed by the yellow details around the gills, creating a sharp contrast against the darker body. Long, flowing and unusually large for a nudibranch, the Regal Sea Goddess has a presence that makes its name feel entirely deserved. Size: Up to around 130 mm Range: Mediterranean Sea and eastern Atlantic, including the Azores, Madeira, Canary Islands and Cape Verde, with populations also...

Mandarin FishSynchiropus Splendidus Electric blue curls across this tiny reef fish in winding bands, tangled with flashes of orange, green and yellow that seem to change with every movement. Its oversized eyes sit high on a gently sloping head, while the long dorsal fin rises behind it in a soft, flowing arc. Rather than darting through the reef, it tends to pick its way slowly across the bottom, stopping constantly to inspect the rubble for something small enough to eat. Size: Up to around 70 mm Range: Western Pacific; from the Ryukyu Islands through the Philippines, Indonesia and New Guinea...

Crested NembrothaNembrotha Cristata Deep burgundy covers the body of this striking nudibranch, scattered with irregular orange spots that glow against the dark surface. A cool blue-white edge traces the underside, while two tall black rhinophores rise from the front like little horns. Behind them, three feathery clusters flare upward in dark red and orange, giving the animal a wonderfully spiky silhouette. It looks less like a soft-bodied slug and more like something that has been built for making an entrance. Size: Up to around 50 mm Range: Indo-West Pacific; from the western Indian Ocean through Indonesia and the Philippines to...

Tambja Kava This one looks like it escaped from a science-fiction movie. The body is an intense, almost fluorescent green, covered in fine reddish lines that give the surface a corrugated texture. Two tall, ridged rhinophores rise from the head like bizarre alien antennae, shifting from reddish brown into deep violet at the tips, while the small gills behind them carry the same dark purple coloring. Even the tail seems to glow, fading into pale translucent lobes with violet tips. Against the fiery reef in the photograph, the effect is completely surreal. It barely looks like a real animal, let...