Formalin practice has been going on unabated in fish markets of Bangladesh due to some unscrupulous trader’s ill intentions and also indulgence by government negligence to check the trends. In order to afford suitable measures to moderate the situation, present study was carried out to investigate the status of formalin laced fish marketing and their impact on human health. The study was conducted in six fish market areas of Dhaka city from June to September 2014. A laboratory test of collected 180 samples of five fish species with formalin detection kit developed by the BCSIR was done to measure whether the fish species are formalin treated or not. Apart from that 120 randomly sampled fish consumers were surveyed in a face to face contact using pre-tested interview schedule. Findings revealed that majority of the consumers buy all types of fishes from open market place on 2days/weekly without checking out the presence of formalin before buying fishes. Consumers are not so concerned about checking out the presence of formalin. However, they observed absence of fly on displayed fish sample as well as freshness of eye and overall body appearance to avoid buying formalin treated fishes. Among the tested 180 fish samples, 11.66% were found formalin treated; of which 25% Rui (tested 36, formalin presence-9) were found contaminated with formalin. Among all formalin treated fishes the rate was found highest in Mirpur-1 bazaar (16.66%) and lowest in Taltola bazar (6.66%). Cough, bronchitis and headache were major perceived health hazards being suffered by the consumers. Consumers should be more conscious about buying Rui (Labeo rohita) fish as it is highly subjected to treatment with formalin.