Fish are aquatic vertebrates that are typically ectodermic (previously cold-blooded), covered with scales, and equipped with two sets of paired fins and several unpaired fins. Fish are abundant in the sea and in fresh water, with species being known from mountain streams as well as in the deepest depths of the ocean. They are of tremendous importance as food for people around the world, either collected from the wild or farmed in much the same way as cattle or chickens. Fish are also exploited for recreation, through angling and fish keeping, and are commonly exhibited in public aquaria. Fish have an important role in many cultures through the ages, ranging as widely as deities and religious