Translucent Leaf Scorpionfish via Maia Valenzuela: 'Lacking any other defense, many larval fish have adapted transparency as a method of camouflage—such as this tiny, see-through larval leaf scorpionfish in Hawaii.' Image credit Chris Newbert #Scorpionfish
Extreme diver Norbert Wu's Journey into the Antarctic underworld: Showing a medusa or jelly (Desmonema glaciale). It lives near the surface and the bell can reach over one meter in diameter. It is incredibly intricate and beautiful though.