1750, a name given to various types of fish deemed exceptionally large or tasty; see king (adj.) + fish (n.). From 1933 as the nickname of U.S. politician Huey Long (1893-1935) of Louisiana.
Entries linking to kingfish
king adj.
king (n.) applied, at first in natural history, to species deemed remarkably big or dominant, such as king crab (1690s); the U.S. king snake (1737), which attacks other snakes and is regarded especially as the enemy of the rattlesnake; king cobra (1888). In marketing, king-size is from 1939, originally of cigarettes. A king-bolt (1825) was the large bolt connecting the fore part of a carriage with the fore-axle.
The King-snake is the longest of all other Snakes in these parts, but are not common; the Indians make Girdles and Sashes of their Skins, and it is reported by them, that they are not very venemous, and that no other Snake will meddle with them, which I suppose is the Reason that they are so fond of wearing their Skins about their Bodies as they do. [John Brickell, "The Natural History of North-Carolina," Dublin, 1737]
fish n.
"a vertebrate which has gills and fins adapting it for living in the water," Old English fisc "fish," from Proto-Germanic *fiskaz (source also of Old Saxon, Old Frisian, Old High German fisc, Old Norse fiskr, Middle Dutch visc, Dutch vis, German Fisch, Gothic fisks), perhaps from PIE root *pisk- "a fish." But Boutkan on phonetic grounds thinks it might be a northwestern Europe substratum word.
Popularly, since Old English, "any animal that lives entirely in the water," hence shellfish, starfish (an early 15c. manuscript has fishes bestiales for "water animals other than fishes"). The plural is fishes, but in a collective sense, or in reference to fish meat as food, the singular fish generally serves for a plural. In reference to the constellation Pisces from late 14c.
Fish (n.) for "person" is from 1750 with a faintly dismissive sense; earlier it was used in reference to a person considered desirable to "catch" (1722). Figurative sense of fish out of water "person in an unfamiliar and awkward situation" attested by 1610s (a fisshe out of the see in the same sense is from mid-15c.). To drink like a fish is from 1744. To have other fish to fry "other objects which invite or require attention" is from 1650s. Fish-eye as a type of lens is from 1961. Fish-and-chips is from 1876; fish-fingers from 1962.