In eight short lines, a trip to buy fish turns into a confession. The title is a proverb, and the poem sets about showing how it works. The fish are "fine"; the sea they come from is "wretched dirty". The buyers see only the first. What was caught in the filth, and who may have been hurt to bring it in, drops out of view, and the poem suggests that this is exactly how a comfortable life is kept comfortable.
The first stanza sets two words against each other, "fine" and "wretched", and the whole poem grows from that gap. It has no verb and no speaker, only a label and a judgement, like a note scribbled beside a market stall. Then "we" arrives: "we bought four." The purchase is almost comically small, and the next line makes it feel less innocent: "easily persuaded almost to anything." The grammar is slightly off, since we expect "persuaded of something" or "persuaded to do something". That unsteadiness fits the idea, because a mind that gives way this easily doesn't care where its sentences end up. The line could describe the shoppers, but it could just as well describe the fish, which were also taken in by whatever bait they met. The poem leaves both readings open.
The third stanza turns into a demand: "offer us love / but never science." It sounds like a plea, but it works as an indictment. Love here means warm, flattering stories, the kind of persuasion that sells things. Science means facts, such as what is actually in that sea. The speaker's group asks to be soothed rather than informed, and the word "never" shows the choice is deliberate. Ignorance is something they ask for.
The last stanza is the most uncomfortable. "Wrong the poor but make me thankful / for being at ease" reads like a twisted prayer. Judging by the first stanza, the poor may be the people who live or work beside the dirty sea, but the poem never says, and that vagueness is part of its point: the victims stay unnamed, just as they are "out of sight." The speaker does not ask to stop wronging them. The request is only to feel grateful afterwards. The sentence also runs on without a pause across the line break, so "thankful" slides straight into "being at ease", as if gratitude and comfort were one feeling. Nowhere does the poem preach. The speaker condemns himself, which is harder to dismiss than a lecture.
The form is as stripped down as the message. There is no rhyme, no punctuation and no capital letters, only four couplets of plain speech. The lines are quick and uneven, short at first ("fine fish") and longer by the end, as though the speaker gets more fluent the more he justifies himself. The pronouns shift too. The first stanza has none, the second has "we", the third "us", and the last "me". The poem moves from an anonymous observation, through a shared habit, to one person's guilt. By the end the reader has been drawn along, from watching a crowd to standing inside it.
Sound ties the poem together quietly. The hard consonants of "wretched dirty" give way to the soft, open vowels of "easily" and "ease". The long *e* of "sea" returns in the final word, "ease", so that the clean, comfortable ending echoes the filthy beginning. Once you hear it, the ease cannot be separated from the sea.
The poem matters because it fits an everyday moral problem into the space of a receipt. Most of us buy things whose origins we do not look at, and the poem suggests that this blindness is partly chosen. It also avoids a tidy answer. It names the fault, the wish not to know, and then leaves us holding our own shopping bags.