There are many ways to rig a live bait. The first is through the back, generally just before the dorsal. The trick is to go deep enough so that the hook will hold well, keep rigid and not rip out.
This is a great rig for John Dory and kingfish.
If you go too shallow the hook can rip out, or the hook may turn and go back into the bait when you strike the fish. When inserting the hook insert the point on a slight angle towards the head, this way it will allow the hook to lay flat along the body when the live bait is swimming.
It will also allow you to strike the fish and drive the hook home easily. Most fish will take a livebait head first so the spines of the fish lay flat on the body and it slides down easily. An added plus is that if the fish tries to disgourge the bait after taking the bait, it will in turn catch the point and you will have a solid hook up.
The second way is to rig it through the nose, this is a quick easy task, and works really well when the bite is hot and you need to get a bait in the water quickly.
All fish have two small nostril holes above the upper lip. Insert the hook through here. This area is a very solid area to place the hook and allows livies to be sent down at depths very quickly with added weight.
The third is through the anal area - just behind the anal area is a great place to slide a hook in.
This often works well on fish which are a bit skittery on the bite, and gives a slightly different action with the bait to dorsal or nose hooked baits.
This rig however can allow the bait to be picked off a little easier, so a bit more time is needed before you strike.