Abstract
The present research was conducted on different life stages (90, 120, 150 and 180-day age) of Indian major carps to check the
growth responses under sub-lethal chronic toxicity of iron. Fish of each age group were stressed with iron for 30 days and
growth parameters viz, average weight, fork and total length before and after exposure of iron were measured. Feed intake
and feed conversion ratio of each fish species were also determined to evaluate the condition and health of fish during the
stress period. Statistical analysis of data showed that age of 150 days for Catla catla, Labeo rohita and Cirrhina mrigala
were the most sensitive in terms of fish growth. All the fish species of 150 days age showed significantly (p<0.05) negative
growth in terms of weight, fork length and total length. Condition factor of control fish reveals that weight gain was
maximum in relation to length of fish as compared to fish kept under chronic exposure of iron. The results also showed that
feed intake increased during stress of iron but this feed does not take part in growth as shown by lower values of feed
conversion ratio (FCR) of all fish species in iron stressed medium. This study concluded that among four age groups sublethal chronic exposure of iron disturbed the feed intake, FCR, growth, condition and fish health in 150-day fish.
