Fish In Focus

Welcome to the Fish section of In Focus, delving into the fascinating world of fish; aquatic, gill-bearing vertebrate with fins and a hard skull, lacking limbs with digits. They are categorized into jawless and jawed, which include cartilaginous and bony fish, as well as extinct groups like placoderms. Most are cold-blooded, but some, like sharks and tuna, can maintain a higher body temperature. The study of these species is called ichthyology.

They first appeared during the Cambrian as small filter feeders, evolving through the Paleozoic. Ostracoderms were the earliest with gills and paired fins, followed by placoderms with jaws in the Silurian. Bony fish, characterized by swim bladders and ossified skeletons, became dominant after the Devonian extinction. They include lobe-finned and ray-finned species, with teleosts being the most prevalent today.

They have been a vital resource for humans, serving as food and in recreational fishing. They also play significant roles in culture, represented in art, religion, and literature.