Notes from NEET topper
Class – Osteichthyes
This group encompasses a wide variety of fishes found in both marine and freshwater environments. They are characterized by their bony endoskeleton and have streamlined bodies. Typically, their mouths are located at the terminal end of their bodies.
These fishes possess four pairs of gills, each protected by an operculum on both sides. Their skin is adorned with cycloid or ctenoid scales, and they are equipped with an air bladder that helps them control their buoyancy in the water. Their hearts consist of two chambers, one auricle and one ventricle, and like most fish, they are cold-blooded, unable to regulate their body temperature (poikilothermic).
In terms of reproduction, they have separate sexes, and fertilization typically occurs externally. The majority of these fishes are oviparous, laying eggs with direct development.
Notable examples include Exocoetus (Flying Fish) and Hippocampus (Seahorse) in marine environments, while freshwater species include Labeo (Rohu), Catla (Katla), and Clarias (Magur). Additionally, some species like Betta (Fighting Fish) and Pterophyllum (Angelfish) are popular choices for aquarium enthusiasts.
