All About Fish
A fish (plural: fish or fishes) is a kind of animal that lives in water, and breathes the oxygen in the water instead of air using
gills, which are special flaps that let them breathe water. There are many different kinds of fish. Fish usually have scales and
fins. They live in fresh water in lakes and rivers, and in salt water in the ocean. Some fish are less than one centimeter long. The
largest fish is considered to be the whale shark, which can be almost 15 meters long and weigh 15 tons.
People eat many kinds of fish. The fish that people eat most include carp, cod, herring, perch, sardines, tilapia, trout, tuna, and many others. Fish are sorted into three groups, white fish, oily fish and shell fish. Some people keep fish as pets. Goldfish are a popular type of pet fish.
Most kinds of fish have bones. Some kinds of fish, such as sharks and rays, do not have real bones (their skeletons are made of cartilage). Some scientists say that these are not real fish, but most people call them fish. Some other animals that live in the sea, such as starfish and jellyfish, are called fish, but are not really fish.
The word to fish is also used for the activity of catching fish. People catch fish with small nets from the side of the water or from small boats, or with big nets from big boats. People can also catch fish with fishing poles and fishhooks with bait. This is often called fishing.
Fish are aquatic vertebrates that are typically 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 (e.g., char and gudgeon) as well as in the deepest depths of the ocean (e.g., gulpers and anglerfish).
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 fishkeeping, 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 symbols to subjects of books and popular movies.