Fishing with creaturebaits can in many situations be very effective, especially if the fish are not that active and not actively hunting for the baitfish.
Creaturebaits works also particularly good in rivers with areas where there are a lot of trees hanging over the water. Insects tend to fall down in the water which the perch eat.
Crayfish immitations has proven to work very good in lakes where the perch feed on crayfish, especially in deeper lakes with rock bottom. In these lakes it's good to rig them on heay jigheads, and fish the bait on our around the areas with rock bottom.