Swimming velocity, avoidance behavior and biomarkers in Palaemon serratus exposed to fenitrothion

► Two behavioral tests were developed for the common prawn. ► Swimming velocity was inhibited in prawn exposed to fenitrothion. ► Prawn was able to avoid toxicant exposure at low concentrations of the pesticide. ► Exposed animals lose the ability to avoid high concentrations. ► Altered behavior may lead to important implications at the population level.