Fish Trap

A Fish Trap gathers things from the water on its own: whatever floats within four blocks, the current carries to its mouth. It is woven from weeping willow switches, and over its mouth a lure stamped with the Tide rune hangs on a little rod. Whatever touches the trap lies down in it, and the funnel won't let it back out.

You can see the catch through the switches. Take it with an empty hand; a hopper under the trap empties it like a chest.