Zoology is divided into several branches, among which is ichthyology. This area is responsible for the study of fish, mainly their behavior and biology, that is, through this area, professionals can study the relationship between fish and the environment in which they live, analyze the behavior of animals and classify species, for example. Currently, more than 25,000 species of fish are known, which makes the area really important. Unlike fish farming, ichthyology deals only with the study of fish, while the first is dedicated to the creation of fish, crustaceans, molluscs and also amphibians. This area is related to others, such as marine biology, limnology and oceanography.
This area of study began in the Upper Paleolithic Revolution and has been developed to this day. During the Prehistoric Era, man began to have a desire to feed on fish and, with that, the first ichthyologists emerged who were great hunters and gatherers who discovered when, where and how to get fish for food.
During the 19th century, George Cuvier, French, and Marcus Elieser Bloch, German, worked together to consolidate knowledge in the field.
Among vertebrates, fish are the most numerous class inhabiting not only the salty waters of the seas and oceans, but also fresh waters of rivers, lakes and dams. It is estimated that approximately 24 thousand species inhabit salt water.
The fish have a hydrodynamic shape – body flattened laterally and elongated -, fins for locomotion, scales and skin with mucus-producing glands that reduce friction with water, in addition to segmenting the trunk muscles, all to facilitate and improve the their performance in their habitat.
They are pecilotérmicos, that is, they have body temperature that varies according to the environment, always staying in temperatures similar to the environment in which they are. They breathe through gills or gills – blood vessels absorb oxygen present in water entering the animal’s mouth, eliminating carbon dioxide.
Fish, like other vertebrates, can be herbivores – feeding mainly on algae – or carnivores – feeding on other spindles, mollusks and crustaceans. There are also some fish in the abyssal areas that are detritivores, that is, they feed on organic remains.
With several sense organs, fish can smell smells thanks to the official bag, but their vision is limited, being from a short distance, besides not distinguishing colors. With their lateral lines – formed by a row of pores – fish can feel the differences in water pressure, currents and vibrations that can be caused by other animals, including predators, helping in their survival.