close up shot of coral reefs with slate pencil urchin

animal aqua aquatic bay beautiful blue brown caution close colorful conservation coral critter danger dive diving echinoderm echinometridae ecosystem endangered fish hawaii heterocentrotus life mamillatus mammillatus marine mauii nature ocean pacific pencil pink poison red reef reefs saltwater scuba sea seascape shot sinai slate snorkeling spike sun tropical undersea underwater urchin water wildlife