I had asked about this same story once before many years ago but with no results so I am going to try again.
A professor in a Creative Writing class I took in the early 90s read it to us but it was from a published book, not written by someone in the class or anything.
Basically it was written from the point of view of a fish but since a fish has tiny brain, it is written in simple declarative sentences almost like a poem. The first and last line are both something like “I am hungry; I must eat.” but it goes on about how it lives among its “brothers” but its brothers are just food. The whole thing is basically about swimming and eating.
It was very short. Written out it would probably have only been a page or a page and half.
I know it isn’t much to go on and I have Googled many times but turned up empty. Does it sound familiar to anyone?