Giant sponge showing how it filters water with the use of dye, Dominica, West Indies, Caribbean, Central America

Giant barrel sponge, Thailand, Southeast Asia, Asia

Humphead bannerfish (Heniochus varius) in a giant vase sponge, Komodo, Indonesia, Southeast Asia, Asia

Giant barrel sponge (Xestosongia muta), and sunburst, St. Lucia, West Indies, Caribbean, Central America

Giant sponge showing how it filters water with the use of dye, Dominica, West Indies, Caribbean, Central America

Giant barrel sponge, Dominica, West Indies, Caribbean, Central America

Giant sponge showing how it filters water with the use of dye, Dominica, West Indies, Caribbean, Central America

Giant sponge showing how it filters water with the use of dye, Dominica, West Indies, Caribbean, Central America

Swim through with giant sponge, Dominica, West Indies, Caribbean, Central America

Giant barrel sponge (Xestosongia muta), St. Lucia, West Indies, Caribbean, Central America

A profusion of hard and soft coral with a giant clam underwater on Tengah Besar Island, Komodo Island National Park, Indonesia, Southeast Asia, Asia

Giant barrel sponges on the spectacular walls off the reefs of Turks and Caicos, West Indies, Caribbean, Central America

Sea cucumbers (Synaptula sp.) on giant barrel sponge (Xestospongia testudinaria), Dumaguete, Negros Island, Philippines, Southeast Asia, Asia

Giant clam (Tridacna maxima) with encrusting sponge, Rongelap, Marshall Islands, Pacific

Sea cucumbers (Synaptula sp.) on giant barrel sponge (Xestospongia testudinaria), Dumaguete, Negros Island, Philippines, Southeast Asia, Asia

Scuba Diver with giant sponge, Cayman Brac, Cayman Islands, Caribbean

Looking upwards giant sponge, corals and sea fans with very blue water, Little Cayman Island, Cayman Islands, Caribbean

Diver looking at Giant Barrel Sponge (Xestospongia muta) in coral reef, Caribbean, Dominican Republic, Central America

Giant barrel sponge and Unicornfish, Raja Ampat Indonesia