Author Hugh McCormick Smith (1865–1941)
English: Portuguese-Man-of-War-Fish. Nomeus gronovii
Subject: Portuguese man-of-war
Tag: Fish
Date 1907
Source/Photographer Smith, Hugh M. (1907) Fishes of North Carolina, North Carolina Geological and Economic Survey, vol.II, Raleigh, NC: E. M. Uzzell & Co.
Source: https://commons.wikimedia.org/wiki/File:FMIB_51424_Portuguese-Man-of-War-Fish_Nomeus_gronovii.jpeg

The man-of-war fish or bluebottle fish (Nomeus gronovii) is a species of fish in the family Nomeidae, the driftfish. It is native to the Atlantic, Pacific and Indian Oceans. It is notable for its ability to live within the deadly tentacles of a siphonophore, the Portuguese man o' war, upon whose tentacles and gonads it feeds.