Fish antibiotics are used in fish farming to treat bacterial diseases of fish. It is common practice in the fish industry, particularly in developing countries, to use large amounts of antibiotics to prevent infection. The antibiotics used are often non-biodegradable and remain in the environment for long periods of time, contaminating soil and ground waters. In farming antibiotics are mixed with food and residual amount of drugs ends up in fish products and poultry, this lead to consumption of antibiotics and metabolites by humans. Five common antibiotics are separated on Primesep C column using LC/MS compatible conditions. Method can be used for quantitative determination of nitrofurantoin, nitrofurazone, furazolidone, furaltadone, chloramphenicol and nitrofurazone in fish products and environment.