Wait one full in-game day. Fish will accumulate in the lit chamber.

The Weir Trap, in the context of Vintage Story, is a type of structure designed to catch fish or other aquatic creatures. Unlike traditional fishing methods, a Weir Trap operates on a passive principle, making it an efficient way to secure a steady supply of food without the constant need for active fishing.

Fish can escape weir traps more easily than from hooks. It is recommended to check your traps frequently to ensure you don't lose your catch. Strategic Placement

Here are three different options ranging from a technical guide to an immersive in-game note.

Day 42. The Drifters groan in the hills, but the river provides.

Best for posting on the Vintage Story forums or a wiki to help other players.

I call it the 'Weir'. Yesterday, I pulled four fat fish from the pit without firing a single arrow. The wolves can keep the forests; I own the river now.