lungfish

UK: /ˈlʌŋˌfɪʃ/ US: (lung′fish′)

Inflections of 'lungfish' (n):

lungfish

npl (Especially as a collective plural—e.g. "Lungfish are able to breathe air.")

lungfishes

npl (Mainly used to talk about different types—e.g. "Of all the lungfishes, the only one that can breathe through its gills is the Australian lungfish.")

WordReference Random House Unabridged Dictionary of American English © 2025

lung•fish  (lung′fish′), n., pl. (esp. collectively) -fish,  (esp. referring to two or more kinds or species) -fish•es. 

1. Fish any of various slender, air-breathing fishes of the order (or subclass) Dipnoi, of rivers and lakes in Africa, South America, and Australia, having a lunglike air bladder as well as gills and growing to a length of 3 to 6 ft. (0.9 to 1.8 m).

• lung + fish 1880–85

Collins Concise English Dictionary © HarperCollins Publishers::

lungfish / ˈlʌŋˌfɪʃ/ noun ( -fish, -fishes)

1. any freshwater bony fish of the subclass Dipnoi, having an air-breathing lung, fleshy paired fins, and an elongated body. The only living species are those of the genera Lepidosiren of South America, Protopterus of Africa, and Neoceratodus of Australia