David Fleetham / Red liomera crab (Liomera rubra) female holding a tail full of eggs in a slate pencil sea urchin (Heterocentrotus mammillatus) at night, Hawaii.

Franco Banfi / Yellow-striped cardinalfish (Ostorhinchus / Apogon cyanosoma) and Narrow-lined cardinalfish (Archamia fucata) shoal amongst Sea urchins (Echinothrix diadema) spines, Lazi Pier, Dumaguete, East Negros...

Alex Mustard / Banggai cardinalfish (Pterapogon kaudemi) swimming over a long-spined sea urchin (Astropyga radiata) Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Solvin Zankl / Red / Edible Chilean Sea urchin (Loxechinus albus) about 5cm size, Comau Fjord, Patagonia, Chile, Atlantic Ocean

Solvin Zankl / Red / Edible Chile sea urchin (Loxechinus albus) on Lampshell (Magellania venosa) Comau Fjord, Patagonia, Chile, Atlantic Ocean

Richard Herrmann / Red Sea Urchin (Strongylocentrotus franciscanus) and Purple Sea Urchin (Strongylocentrotus purpuratus) feeding on Southern Sea Palm (Eisenia arborea) creating urchin barren, Santa Cruz Island, Channel...

Pascal Kobeh / Colony of Red sea urchins (Strongylocentrotus franciscanus) at the feet of Bull kelps (Nereocystis luetkeana) Vancouver Island, British Columbia, Canada. Pacific Ocean.

Scott Leslie / Northern Red Sea Anemone (Tealia felina) among Green Sea Urchins (Strongylocentrotus droebachiensis), Passamaquoddy Bay, Maine

Franco Banfi / Giant red sea urchin (Strongylocentrotus franciscanus) Vancouver Island, British Columbia, Canada, Pacific Ocean

Pascal Kobeh / Slate pencil urchin (Heterocentrotus mamillatus), New Caledonia, Pacific Ocean.

Pascal Kobeh / Underwater reef covered with a colony of Red sea urchins (Strongylocentrotus franciscanus), Alaska, USA, Gulf of Alaska. Pacific ocean.