Bishop was poet Marianne Moore's accomplice in trimming the hair off of an elephant (as a replacement for an elephant hair bracelet Moore owned) at the Ringling Bros. and Barnum and Bailey Circus in the spring of 1935 (source: "Efforts of Affection: A Memoir of Marianne Moore").
Bishop didn't just write about fishing, she also fished. In a 1939 letter (she completed "The Fish" in 1940) to Marianne Moore she wrote about on fishing experience: " The other day I caught a parrot fish, almost by accident. They are ravishing fish – all iridescent, with a silver edge to each scale, and a real bill-like mouth just like turquoise; the eye is very big and wild, and the eyeball is turquoise too – they are very humorous-looking fish. A man on the dock immediately scraped off three scales, then threw him back; he was sure it wouldn't hurt him" (source).
Bishop wasn't sure if "The Fish" was a good poem. When she sent it to her friend Marianne Moore, she wrote: "I am sending you a real "trifle" ["the Fish"]. I'm afraid it is very bad and, if not like Robert Frost, perhaps like Ernest Hemingway! I left the last line on so it wouldn't be, but I don't know …" (source).
In a 1978 interview, Bishop declared that she rather have anything anthologized except "The Fish"! (source).