The communication, dealing with the prevalence of protozoan parasites of the ornamental fish of West Bengal. During the study more than five hundred fish have been examined from five districts namely, Nadia, Hooghly, Howrah, North 24-pargana and South 24-pargana of West Bengal during pre-monsoon, monsoon and post-monsoon season. The study reveals that the intensity of infection is more in case of ciliate parasites. The highest ectoparasitic infection has been recorded during post-monsoon season, i.e. from November to February, followed by the pre-monsoon period while the lowest infection was recorded during monsoon i.e. from July to October which may lead to the conclusion that environmental factors are responsible for spreading infection.