There are indeed fish that do not have scales. While scales are a common feature among most fish species, there are some exceptions. These scaleless fish have distinct characteristics and are found in various habitats around the world.
One example of a scaleless fish is the Redtail catfish (Phractocephalus hemioliopterus). Native to the Amazon River basin, this large freshwater catfish can grow up to several feet in length. It has a smooth, scaleless skin that is dark gray or black in color, with a striking red tail fin. The lack of scales allows the Redtail catfish to move more easily through the water and navigate its environment.
Another scaleless fish is the Zebra catfish (Brachyplatystoma juruense), also known as the Juruense catfish. This species is found in the rivers of South America, particularly in the Amazon and Orinoco basins. Like the Redtail catfish, the Zebra catfish lacks scales and has a smooth, streamlined body. It has a silver-gray coloration with dark stripes, resembling the patterns seen on a zebra, hence its name.
The Tiger sorubim (Pseudoplatystoma tigrinum) is another scaleless fish found in South America, primarily in the Amazon and Paraná River basins. This large predatory catfish has a slender body and a unique pattern of dark stripes and spots, resembling that of a tiger. The lack of scales allows the Tiger sorubim to glide effortlessly through the water as it hunts for its prey.
It is important to note that while these fish may lack scales, they still have a protective layer on their skin called “dermal denticles.” These denticles are small, tooth-like structures that provide some level of protection against predators and parasites. Although they may not be as prominent or robust as scales, they serve a similar purpose of safeguarding the fish’s body.
There are several species of scaleless fish, each with its own unique characteristics and adaptations. These fish have evolved to thrive in their respective habitats without the presence of scales, relying on other mechanisms for protection and survival. Exploring the diversity of scaleless fish provides us with a fascinating glimpse into the incredible adaptations that have occurred throughout the evolution of these aquatic creatures.