This red encrusting sponge (Clathria sp.) is the most common of this family found in Hawaii. Here it has covered the calcium carbonate-producing seaweed, Halimeda kanaloana, Hawaii, United States of America

algae calcium carbonate clathria close up color image halimeda kanaloana hawaii hawaiian islands horizontal marine life nature no people ocean ocean floor pacific ocean red red encrusting sponge reef seaweed soft sponge tropical climate underwater water vermilion clathria sponge bright vibrant calcium carbonate close up halimeda hawaiian kanaloana no one nobody pacific sponges tropical