Fish hook with some form of corrosion-resistant surface coating. Corrosion resistance is required not only when hooks are used, especially in saltwater, but while they are stored. Additionally, coatings are applied to color and/or provide aesthetic value to the hook. At a minimum, hooks designed for freshwater use are coated with a clear lacquer, but hooks are also coated with gold, nickel, Teflon, tin and different colors. There are a large number of different types of fish hooks. At the macro level, there are bait hooks, fly hooks and lure hooks. Within these broad categories there are wide varieties of hook types
Bait ball Bait ball A bait ball, or baitball, occurs when small fish swarm in a tightly packed spherical formation about a common centre. It is a last-ditch defensive measure adopted by small schooling fish when they are threatened by predators. Small schooling fish are eaten by many types of predators, and for this reason they are called bait fish or forage fish. For example, sardines group together when they are threatened. This instinctual behaviour is a defense mechanism, as lone individuals are more likely to be eaten than an individual in a large group. Sardine bait balls can be 10–20 metres