The poem begins with a conditional statement: "sometimes you see mudfish." The speaker addresses the reader using the second person, which immediately submerges the reader in the world of the poem. It's also interesting that the speaker doesn't use the word "eels," but instead opts for "mudfish"—another name for the mysterious ever-changing creatures, which "you" can never expect (and only "sometimes" hope) to see.
The speaker uses figurative language to describe the way eels look and act. They're "short lead lengths," a metaphor comparing the eels to lead pipes based on the way their gray, cylindrical bodies look when they're at rest, and they "hide at low tide" while "roping and wagging," moving like ropes or dog tails. These are strange, skittish animals.
The speaker's next descriptions lean towards the mythic and abstract. They call eels "preliminary, pre-world creatures, cousins of the moon"—almost placing these strange beasts on a pedestal, or elevating them to a level worthy of worship:
- "Preliminary" suggests that eels, with their sleek bodies, are some evolutionary relic; they're a starting point for later, more complicated animals. They are utterly ancient.
- Likewise, they're "pre-world": they belong to a time before the world as human beings know it even existed.
- Finally, they're "cousins of the moon"—something utterly alien, not of the earth itself. The moon is often a symbol of mystery and magic, further conveying the otherworldly strangeness of the eels.
Part of what makes eels so intriguing is their evasiveness, of course. If they weren't so hard to spot, the poem implies, then they wouldn't be so fascinating! The speaker states that eels "love blackness, aloofness"—personifying them as cold, solitary creatures who prefer their own company and move only "under cover of the unmoon." In other words, they don't emerge until clouds pass over the moon, obscuring its light.
Notice how the hissing sibilance of "blackness, aloofness" evokes the eels' swift, slithery movements. Indeed, the poem is filled with sonic devices that bring its slippery imagery to life. Listen to these devices at work in lines 1-3:
sometimes you see mudfish,
those short lead lengths of eels
that hide at low tide
Sibilance (those /s/ and /sh/) sounds cast an eerie hush over the poem, while liquid /l/ sounds evoke the creatures' smooth, fluid motions. Assonance ("lead lengths") and internal rhyme ("hide"/"tide") make the length yet more rhythmic and hypnotic.