Green’s Dictionary of Slang

used of someone who, whatever they may believe, is not unique (esp. in the context of love affairs); thus plenty more fish in the sea, an encouraging phr. said to one who is going through a relationship breakdown.

1888		M.C. Rowsell Red House 129: ‘I am surprised,’ he said, ‘But the lady is not the only fish in the sea.’ ‘She was a great catch.’ ‘But money is not everything.’.
1914		Bulletin (Sydney) 31 Dec. 44/2: Cheer up, old darling. There’s more fish in the sea, and more pebbles on the beach, and more cards in the pack.
1939		D.L. Sayers In the Teeth of the Evidence 306: You’re not the only fish in the sea by a long chalk. One born every minute.
1941		S.H. Kraines Therapy of the Neuroses and Psychoses 67: Her marriage was to ‘show him that he was not the only fish in the sea’.
1959		B. Kops Hamlet of Stepney Green Act I: Anyway – I’m not that hard up – plenty more fish in the sea.
1974		J. Heller Something Happened 446: You’re not the only fish in the sea, baby.
1985		D.J. Grzesiek Financial Independence 228: When the prospective tenant arrives and finds that he is not the only fish in the sea, he is not likely to act as though he is God’s gift to landlords.
1996		Rotarian June 14: Is that so! Well, you’re not the only fish in the sea!
2004		The Streets ‘Dry Your Eyes’ 🎵 Dry your eyes mate / I know it’s hard to take but her mind has been made up / There’s plenty more fish in the sea.

not alone, not the only person who is equally qualified.

1906		E. Pugh Spoilers 113: You ain’t the only onion in the soup. We got lashin’s o’ friends!
1919		H.C. Witwer Smile A Minute 149: I ain’t jealous of my baby, or nothin’ like that, but I must say I am bein’ made to feel that I ain’t the only onion in the hash right now.
1934		Wodehouse Right Ho, Jeeves 59: Without having everybody behave as if Jeeves was the only onion in the hash.
1960		Wodehouse Jeeves in the Offing (2002) 175: But that’s the whole idea, to show her she isn’t the only onion in the stew and that if she doesn’t want me, there are others who feel differently.

used of someone who, whatever they may believe, is not unique (esp. in the context of love affairs).

1896		H. Braisted ‘You’re not the only pebble on the beach’ 🎵 If you want to win her hand, Let the maiden understand That she’s not the only pebble on the beach!
1906		E. Dyson Fact’ry ’Ands 128: S’ elp me shicker, Twenty, you was the on’y pebble.
1909		F. Murry [perf. Marie Lloyd] Rosie had a very rosy time 🎵 Johnnies each of ’em thought her a peach / And the only pebble upon the beach.
1910		Bulletin (Sydney) 3 Nov. 32/1: If Joy be always with you and you never meet a woe, / If Pleasure clip you closer than a leech, / Keep your hand upon your collar and be sparing with your crow – / You’re not the Only Pebble on the Beach.
1922		Joyce Ulysses 253: Think you’re the only pebble on the beach? Does that to all. For men.
1960		(con. 1940s) D. MacCuish Do Not Go Gentle (1962) 129: You ain’t the only turd that’s been on the road.
1962		(con. WWII) J.O. Killens And Then We Heard The Thunder (1964) 178: You think you’re the only pebble on the beach.

(Aus.) used of someone who, whatever they may believe, is not unique (esp. in the context of love affairs).

1907		Sun. Times (Perth) 31 Mar. 1/1: A recent snubbing has set him thinking that he isn’t the only turtle in the tank.
1910		L. Esson Woman Tamer in Ballades of Old Bohemia (1980) 62: You ain’t the only silver fish in the pond.
1911		E. Dyson ‘The Rivals’ in Benno and Some of the Push 155: He ain’t th’ on’y sardine in the tin. Put on yer spring millin’ry, get out after a squatter, why don’t yeh?