Anil Kumar & Arun Kumar*
University Department of Zoology, B.N.M.University, Madhepura, Bihar, India
Received : 12th December, 2019 ; Revised : 9th February, 2020
Abstract: Whenever an organism’s body or part of the body is deprived of adequate amount of oxygen supply at tissue level, on condition generally called as hypoxia develops. Fishes generally depend on dissolved oxygen in water for their respiratory needs. And this dissolved oxygen usually depends on various factors such as surface area of water, temperature, etc. so for survival of fishes, a constant concentration of dissolved oxygen is a must. This paper deals with the causes and effects of fishes.