10 Interesting Facts About Fish

Fish have been living on Earth for more than 500 million years, they have been around for a long time on planet Earth even before the dinosaurs, and there are more than 25,000 species of fish, so there are more species of fish than all types of amphibians, reptiles, birds and mammals.

But the puzzling question remains, which is what distinguishes fish from other animal classes, fish come in a category of aquatic vertebrates, they combine gills and fins, and the fact that fish live only in water makes them different from other animals, fish spend their entire lives in water and are cold-blooded animals with the exception of the tuna, shark and mackerel families.

Scientists believe that there are more than 24,000 different species of fish in the world, which have not yet been identified. This applies to more types of fish than amphibians, reptiles, birds, and mammals. Most fish have a skeleton made of bone, but some of them, such as sharks, have a skeleton made of cartilage. We find that fish are divided into three main groups, including cartilaginous fish, bony fish, and fish with fins. Cartilaginous fish are called by this name because their body frame is made of cartilage instead of bone, which makes them more flexible. This cartilaginous structure enables the fish to grow to incredible sizes. Finned fish are the most diverse of the three groups of fish, and include a group of 23,000 species, including trout, lantern fish, herring, electric eels and many others. There are approximately 24,000 species of finned fish that are divided into 431 families, which are in contrast to cartilaginous fish.

These are some of the 10 most interesting facts about fish:

1- Some fish migrate from the sea to freshwater rivers to spawn, such as salmon, and unlike other species that migrate from freshwater to the sea to spawn, such as freshwater eels.
2- Fish move in the water by creating a wave motion that makes them move along their body. This motion starts in the head and moves to the sides, which results in the propulsion force that helps the fish move through the water.
3- Fish are cold-blooded animals, so their internal body temperature is the same as the temperature of the surrounding water.
4- Many species of tilapia incubate their eggs in their mouths after the eggs hatch. After hatching, the parent continues to use the mouth to provide shelter for the young.
5- There are two groups of jawless fish alive to this day. These fish were a diverse group of fish that appeared 500 million years ago. Today, jawless fish are represented by eels and hagfish.
6- Cartilaginous fish are the largest and most skilled marine predators in the sea, especially those fish that have skeletons made of cartilage, not bones, as cartilaginous skeletons are more flexible than bones.
7- Even today, fishing is still the most dangerous job in the world, as many fishermen are exposed to danger, and they face a higher death and injury rate than even firefighters or police.
8- There are some types of fish that are unable to absorb oxygen from the water, so they absorb oxygen from the air and crawl on land using strong pectoral fins.
9- Some fish, such as sharks, do not have an air bladder that helps them maintain their position standing on their feet, so we find them constantly swimming or resting on the bottom.
10- Fish breathe through gills on the sides of their heads, which allows fish to breathe underwater, but fish return to the surface of the water to breathe air, but at varying intervals. The electric eel is one of the fish that can go for up to 10 minutes without appearing in the air.
Source: kenanaonline.com