Answer: It follows Imagist rules.
Explanation: Similar to the Imagists, for the author Marianne Moore common objects of nature are the baseline of her poems. Analyzing her work “The Fish,” we can tell that her observations of nature turn out as images by describing textures, shapes, and colors in such a precise manner that William Pratt, a critic, added the poem into one of his books "The Imagist Poems" published in the year of 1963, and which is considered to be definitive text on the Imagist movement. It follows the rule of Direct treatment of the “thing”, whether subjective or objective stablished by Ezra Pound.