What is Pike by Ted Hughes trying to tell??
I think your assessment is correct, but with a good poem the interpretation never stops at a single, static answer when you come back to it a second or third time or fourth time. Poems aren’t like equations because the answers that come forth may be manifold. You may find new meaning in a line you hadn’t considered before, or you as the reader may have changed in your own life which may change the meaning of a poem for you. There are plenty of rich images to consider which one can attempt to imbue with significance. He describes the pike in various modes. One of the more fascinating ones for me is his description of the two pike dead and dry on the bank, except one had halfway swallowed the other (6th and 7th stanza)! We could import our own significance as human beings to this image, the idea of competition and survival ultimately can mean doom for the two parties involved. It also speaks to the powerful yet ultimately decaying legacy of supposedly powerful fish. And on a simple descr