Fish are a diverse group of animals that live in the water. Fish are classified as chordates because they have a backbone and pharyngeal gill slits, although these characteristics were not present in the ancestral fish.
Short And Long Paragraph On Fish
Most fish are ectothermic (cold-blooded), which means that their internal body temperature matches that of their surroundings. However, certain deep-sea fish maintain a higher body temperature than the surrounding water through physiologically generated heat and insulated protection from cold water.
The term “fish” is most precisely defined as an animal swimming in water with fins and scales. Many types of aquatic animals, such as jellyfish, cephalopods (squid and octopus), echinoderms (starfish and sea urchins), and crustaceans (lobsters, crabs, and shrimp), are not fish but are commonly referred to as seafood.
There are more than 28,000 different species of fish that have been identified, making them the second-largest group of vertebrates on earth after mammals. Fish come in a variety of shapes and sizes, from 5 cm (5 cm) seahorses to 9 m long whale sharks. Some fish are monotonous and camouflaged to hide from predators, while others are brightly colored, like the tropical angelfish. Some fish live in saltwater, while others live in freshwater. Many fish migrate long distances to spawn in different bodies of water.
Fish are abundant in all bodies of water, from the top layer of the ocean to deep underwater trenches. Most fish have streamlined bodies like torpedoes that reduce the friction from the water and help them swim quickly.
Many species jump out of the water to catch prey or to avoid predators. The dolphin is something of an iconic example, but most fish propel themselves out of the water by quickly moving their caudal fin back and forth (pumping). Large fish like tuna can even boost speed faster than dolphins. You can also jump high enough above the surface for considerable distances to catch seabirds flying close to the surface; tuna catches are widespread off Santa Catalina Island, California.
A blister-like layer of skin on some fish helps them swim faster. This layer, known as the myotomal gladius (Latin for sword), is made up of a protein called collagen, which is very tough and elastic. In some fish species, the gladius can make up to 20% of their body weight.
Because fish are ectothermic, they rely on their external environment to regulate their body temperature. To save energy, they often live in water temperatures close to the ambient temperature. Warm-blooded animals such as mammals generate heat internally and can maintain a body temperature much higher than that of their surroundings. This enables them to be more active and efficient hunters. Endothermic (warm-blooded) fish are a rarity and only occur in a few groups, such as tuna, mackerel, and billfish.
Fish has been part of the human diet since prehistoric times. They are an important source of food in many cultures, and their versatility means that they can be prepared in many ways. Popular fish dishes include fried, grilled, baked, steamed, poached, boiled, microwave-cooked, and even raw fish. Some people are allergic to fish. This allergy is caused by a protein in fish meat that the body mistakenly considers harmful.
Conclusion
Fish farming is a rapidly growing industry that has helped make some species of fish more affordable and accessible to consumers. Overfishing and illegal fishing practices, on the other hand, cause some fish populations to dwindle to unsustainable levels, so it is critical to source seafood from sustainable sources whenever possible.
