Fish are aquatic animals.
Aquatic animals are those living beings belonging to the kingdom Animalia that spend most of their subsistence in water . This does not mean, however, that these are only animals capable of breathing underwater, but that there are aquatic animals that must come to the surface to capture oxygen .
Before going fully into defining the concept, we are going to proceed to determine its etymological origin. When we do so we discover that the two words that give it shape come from Latin: animal comes from "animal" , which can be translated as any being that has breathing; and aquatic , which derives from aquaticus . This term is composed of the noun aqua (which is synonymous with "water" ) and the suffix -tico (which is used to indicate "relative to" ).
It should be noted that animals are those living beings that are part of the kingdom Animalia , they can move on their own, they reproduce sexually, they absorb oxygen when breathing and ingest food. The concept, in its broadest sense, includes Homo sapiens , although use of the term is generally limited to non-rational animals . Aquatic , for its part, is an adjective that refers to what is linked to water . The word is usually used with reference to those beings that live in it or to objects that, by their nature, remain in the water constantly.
Characteristics of aquatic animals
Although there are many different types of aquatic animals, it is important to know that they all have a series of common characteristics such as these shown below:
- They have had to adapt to the sea, specifically to its tides and the different water currents that occur. Hence, some have fins, others have basal discs, some have shells...
- No less important is that the nutrition of these living beings, in one way or another, depends on phytoplankton, which is a species of plant that lives in the sea and is microscopic. And it is located in the nutritional base of these animals.
- It should also be noted that they have also had to adapt to the water temperatures, so each class has mechanisms that achieve this: scales, pale blood...
Some aquatic animals are mammals, such as the dolphin.
Fish and other species
Fish are the most representative example of aquatic animals. These vertebrates have gills to breathe underwater, so they do not need to leave the water: in fact, when they are removed from their environment, they die. Fish have fins for swimming and usually have their bodies covered in scales.
Other aquatic animals, however, must rise to the surface to breathe. This is the case of the dolphin , a mammal that has a single blowhole to absorb oxygen from the air.
It is important to note that there are aquatic animals that also spend a good amount of time on land , which is why they are usually classified as semi-aquatic. Beavers and hippos , for example, are in this group.
It must be taken into account that within the group of aquatic animals there are several that are in danger of extinction, such as the Mediterranean monk seal , the sea otter , the gray whale or the wrasse , among others.