In the first four stanzas of this free verse poem, the voice is objective, a much like a third-person narrator. The narrator describes the scene stoically, seemingly with no emotion. Therefore, the speaker/narrator can describe the brutality of the pike with a quiet, almost respectful detachment. The descriptions are clear, visually oriented and direct, making the pike come alive. As "malevolent" as the pike is described, the speaker notes that this is its nature: "A life subdued to its instrument;" (15).
The speaker's voice changes in the fifth stanza. The third person narration shifts to first with "Three we kept behind glass,"; the speaker has brought the predatory pike and imprisoned it in his world. In the fifth and sixth stanzas, the speaker gives a more striking example of the pike's brutality. The speaker notes that of the three pike he'd kept in an aquarium, only one remains; indicated that the pike ate each other. Then he provides an image of two dead pike on shore, one in the process of eating another: "And indeed they spare nobody."
In the final four stanzas, the speaker is actively confronting the pike. We see the speaker's fear emerge as he fishes for the brutal fish:
Pike too immense to stir, so immense and old
That past nightfall I dared not cast
But silently cast and fished
With the hair frozen on my head (35-38)
The structure of these three sections involves a progression in which the speaker 1) observes the pike and acknowledges the necessity of its predatory nature, 2) invades the pike's world and imprisons it only to discover that its nature can not be inhibited, and 3) realizes that he, not the pike, is the predator; he intruded by imprisoning the pike in the aquarium and he felt like the intruder even standing on the bank of the pond.
Just as he observed the pike, wondering about its nature, the pike looks back at him with the same objective but judgmental gaze. Over the course of the poem, the voice shifts from one judging the pike to one being judged by the pike. This leaves the question of who the real intruder or the real predator is: human or pike.