Question: there are plenty of fish in the sea origin?
Answer: : "There are other fish in the sea." ... First attested in the United States in _Keziah_ by J. C. Lincoln, the proverb is found in varying forms: "There are plenty more fish in the sea"; "There are more fish in the sea than ever came out of it"; "The sea is full of other fish"; "There's more than one fish," etc.