A "tip-up" is a type of fishing device used primarily for ice fishing. It consists of a frame that holds a fishing line and a flag. When a fish bites the bait, the line pulls free, causing the flag to tip up, signaling the angler that a fish is on the line. Tip-ups are popular because they allow anglers to monitor multiple lines at once while remaining in one spot. They can be used with various bait types and are effective for catching species like pike, walleye, and trout. This method enhances the fishing experience during winter months.