hola, esteem!
Fish are members of poichilothermic vertebrates (cold-blooded) [1] who live in water and breathe with gills. Fish are the most diverse group of vertebrates with more than 27,000 species worldwide. Taxonomically, fish belong to the paraphyletic group whose kinship relationship is still debated; usually fish are divided into jawless fish (Agnatha class, 75 species including lampreys and hag fish), cartilaginous fish (Chondrichthyes class, 800 species including sharks and rays), and the rest are classified as hard-bone fish (Osteichthyes class). Fish in various regional
languages are called iwak (jv, bjn), jukut (vkt).