In the review section on this site there is a review of William Faulkners, As I Lay Dying. The review includes an interesting comment from one of Addie's five children, Vardaman, when he says after she dies, that he believes she is a fish.
When he said this Vardaman had recently caught a fish and then he had cut it up into little pieces; once it was cut up, it was no longer a fish. The comment he makes, “My Mother is a fish”, stands out as odd. We may ask ourselves why Faulkner had Vardaman say this?
Perhaps it is conciseness taken to a new level, cutting out unnecessary words while conveying an idea enhancing communication by eliminating redundancy? Was it meant to be profound, metaphorical or just show a very poor understanding of death? Maybe it was religious intending to show that mom was no longer in the box but fish would be soon?
So a fish was previously caught and it was a fish, and then it was cut up and it was not a fish. Or, as Vardaman sees it, and says it, it was a fish and now it’s a not-fish.
Addie was his mother, and then she was not his mother, the same as for the fish, she is a not-mother, so she must be a fish.