What is a livebait rig
A livebait rig is a rig where a live fish serves as the bait while the rig itself stays put. The predator takes the baitfish and moves off to the side with it; everything else in the rig is built so that nothing gets in its way at that moment.
How it's built
A reserve of line on a winder or a reel, a sinker, a leader and a hook with the baitfish. The sinker holds the fish at the right depth, the leader keeps the line from being bitten through, and the reserve of line lets the predator move off without dragging the rig along.
Why free-running line matters
If the line doesn't run, the predator feels resistance and drops the baitfish before swallowing it. So the reel is set to turn at the slightest pull, and the line is laid loosely, with no loops and no pinch points. This is the main requirement for the whole design, and everything else in it comes second.
The hook for the baitfish
Single, double or treble — the choice depends both on how the baitfish is hooked and how long the predator is given to swallow it, and on which predator is biting: pike crush the baitfish crosswise, a zander's jaw is harder to set a hook in and needs a finer wire hook. The ways of hooking it are in a card of their own, the types of hook in the section on hooks.
What the setting depth decides
The baitfish is set so it swims in its own layer, not lying on the bottom and not hanging right under the ice. That's done with the sinker and the length of line from it to the hook — two details that change everything, and the first ones to move when there are no bites.
The sinker: sliding or fixed
A sliding sinker lets the predator pull the line without lifting the metal — which is exactly why it's used more often. A fixed one is simpler and doesn't shift the depth, but it adds resistance right at the bite. What a sinker actually is has a card of its own.
What it is not
It isn't a bottom rig with a dead bait: there it's scent and a motionless bait doing the work, here it's the baitfish's own movement. And it isn't a winter jigging rod either: in vertical presentation the hand sets the action, here the fish sets it itself.
What we don't cover here
Not how many such rigs are set, and not where the baitfish comes from — that's the territory of rules that differ by region. And no sizes either: the fish has to be the size the local predator takes, and that gets checked on the water, not in a reference guide.