🌊 Waves at the surface bend sunlight into bright, wobbling lines on the bottom. Optics calls them caustics, from the Greek for burnt. Here they fall through gaps in a reef overhang at Shaab Sheer, Safaga, onto white sand. #caustics #ShaabSheer #Safaga #RedSea

🐠 A coral hind holds its ledge at Gamul Kebir, blue spots on red, and waits. Over 80 % of what it eats is small fish, mostly sea goldies, taken in one rush up from the bottom. A few metres on, the reef top is a cloud of orange anthias in the light this shallow reef is known for. #coralhind #grouper #anthias #GamulKebir #RedSea

🫧 Out of the deep blue, mouth wide, then overhead so close its wing blocks the sun. The Maldives is home to the largest known population of reef mantas in the world, a whole nation of them gliding past the atolls. #mantaray #maldives #mantas #underwater #bluewater

🧠 Manta rays have the largest brain of any cold-blooded fish, both by weight and for their body size. They take their time with life too: mantas may live at least 50 years. And no stinging spine in the tail 💙 Just wide wings over the reef and the light coming down from above. #mantaray #manta #gentlegiant #oceanlife #underwater

💤 Upside-down jellyfish were the first animals without a central nervous system seen to sleep: they pulse slower at night, and kept awake, they are sluggish the next day. This Cassiopea, in full daylight at Shaab Sheer, is up and swimming, frilly arms pointed at the sun. #cassiopea #upsidedownjellyfish #jellyfishsleep #shaabsheer #redsea