David Fleetham / Sargasum frogfish (Histiro histiro) near the surface floating on discarded polypropylene rope, Hawaii.

Pete Oxford / Broadleaf Gulfweed (Sargassum fluitans) floating mat, Ambergris Caye, Belize

Solvin Zankl / Sargassum fish (Histrio histrio) in Broad-toothed gulfweed (Sargassum fluitans) Sargassum Community. Sargasso Sea, Bermuda

Solvin Zankl / Sargassumfish (Histrio histrio) swimming near Broad-toothed gulfweed (Sargassum fluitans) Sargassum Community. Sargasso Sea, Bermuda.

Solvin Zankl / Tiny crab on Broad-toothed Gulfweed (Sargassum fluitans) Sargassum Community. Sargasso Sea, Bermuda

Juergen Freund / Sargassum seaweed (Sargassum sp) floating on the sea surface, Palawan, Philippines, May

Juergen Freund / Sargassum frogfish / anglerfish (Histrio histrio) in its floating Sargassum seaweed home, El Nido, Palawan, Philippines

Juergen Freund / Sargassum frogfish / anglerfish (Histrio histrio) in its floating Sargassum seaweed home, El Nido, Palawan, Philippines

Juergen Freund / Sargassum frogfish / anglerfish (Histrio histrio) in its floating Sargassum seaweed home, Miniloc island in the background, El Nido, Palawan, Philippines.

Norbert Wu / Atlantic Spotted Dolphin (Stenella frontalis) playing with Sargassum weed, Little Bahama Bank, Caribbean

David Shale / Sargassum frogfish (Histrio histrio) camouflaged on Sargassum seaweed off Cape Verde Islands, Atlantic. Seaweed floats in large masses on sea surface

Alex Mustard / A raft of sargasso weed (Sargassum natans) in open ocean. Off shore, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.