Four short lines, and a whole feeling of settling in. The speaker is fishing, and the poem starts by placing us right at the spot: the place where fish move through the water and feed. There's nothing fancy about the setup. It's just a person watching and waiting where life is busy beneath the surface.
The turn comes in the third line, when "I" becomes "we." The speaker seems to merge with the fish and the scene around them, and together they "fall into greater order." That word "fall" matters. It suggests something easy and unforced, like slipping into sleep rather than making an effort. The last line, "into a music," gives the feeling a name. Eating, moving, casting, and waiting begin to sound like one rhythm.
The mood is calm and quietly joyful. The poem doesn't explain this music; it just lets the idea hang there, as if the speaker is sharing something that can't quite be put into more words.