A comparative study on the sensitivity of selected freshwater fishes against triclosan exposure.

Triclosan, a broad-spectrum antimicrobial agent, which is widely used in several pharmaceutical and personal care products, has been known to pose adverse impacts on various groups of aquatic organisms, including fish. The present study aimed to compare the sensitivity of five selected freshwater fishes toward triclosan exposure. The acute toxicity or median lethal concentration (LC-96 h) of triclosan determined using probit analysis was 1.76 mg L in , 448 µg L in , 700 µg L in , 1.35 mg L in , and 750 µg L in Based on the length-weight relationship, the lowest condition factor, or value, was recorded in (0.931) while the highest value was observed in (2.343) indicating negative allometric growth. Similarly, the weight of fishes and gill weight declined significantly ( < 0.05) in their respective LC-96 h groups with concomitant alterations in the rate of oxygen consumption denoting respiratory distress. Triclosan exposure also resulted in the modification of fish behavior and histomorphological damage in gill tissues. The alterations in all parameters tested were more prominent in and thus considered the most sensitive species, while comparatively tolerated the toxicant to some extent. The study provides the baseline data that variation in the length-weight relationship is one of the major factors that influences the toxic effects of triclosan on the selected freshwater fishes.