An ideal water condition is a necessity for the survival and good growth of fish since the entire life processes of the fish is wholly dependent on the quality of its environment. These water quality parameters become more critical in intensive culture systems where fish is raised in artificial ponds with reduced self purification capabilities as compared natural systems. Ichthyology (from Greek: ?????, ikhthus, "fish"; and ?????, logos, "study") is the branch of zoology devoted to the study of fishes. This includes skeletal fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). The study of fish dates from the Upper Paleolithic Revolution (with the advent of ''high culture'').Ichthyology is simply the science of studying fishes.