Green’s Dictionary of Slang

1. a male homosexual who openly associates with women, with the supposed aim of appearing to be bisexual.

1949

‘Swasarnt Nerf’ et al. Gay Girl’s Guide 9: fish-queen: [...] Any homosexual who makes a point of bringing women with him where they’ll be seen by his friends, with the apparent aim of convincing himself and others he’s bisexual.

2. (US gay) any man, homo- or heterosexual, who enjoys cunnilingus.

1941		G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
1949		‘Swasarnt Nerf’ Gaedicker’s Sodom-on-the-Hudson 11: For the benefit of fish-queens more dikes are likely to be found at Terry’s.
1951		D.W. Cory Homosexual in America 104: Best known among these words are fairy [...] queen (an important variation being fish-queen).
1961		‘Lou Rand’ Gay Detective (2003) 88: He was suddenly lost to view as he buried his head in the girl’s lap. [...] ‘Get that fish queen!’ simpered Johnnie.
1972		B. Rodgers Queens’ Vernacular.

3. (US gay) a heterosexual man.

1972

B. Rodgers Queens’ Vernacular 81: fish-queen (dated) [...] 2. (pej) any heterosexual man.