What is a Fish?
A fish is an aquatic vertebrate animal that has fins, scales, and is ectothermic. Fish can be found in most any aquatic habitat, from streams to deep ocean environments. The term “fish” most accurately describes any animal with a skull and generally a backbone that has gills throughout its life and has fins. Although many animals that live in the water are called fish, like shellfish, true fish are referred to as finfish to distinguish them from these other animals.
A fish generally has a streamlined body adapted for swimming rapidly through the water. It generally uses gills to extract oxygen from the water, and it has two sets of paired fins: usually one or two dorsal fins, an anal fin, and a tail fin.
Fish range in size from less than ½-inch long to the huge whale shark that grows to 52 feet in length.
Every fish is dependent on water, and everything we put into water eventually will affect the fish population in some way. In addition, fishing practices worldwide are damaging fish populations by destroying habitats, depleting numbers, and polluting the water.