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 in diameter and extend to a depth of 10 metres. The bait balls are short-lived and seldom last longer than 10 minutes. However, bait balls are also conspicuous, and when schooling fish form a bait ball, they can draw the attention of many other predators. As a response to the defensive capabilities of schooling fish, some predators have developed sophisticated countermeasures. These countermeasures can be spectacularly successful, and can seriously undermine the defensive value of forming bait balls. Small pelagic fish live in the open water, so unlike demersal or reef fish, they cannot hide among kelp, or in crevices