the effects of color lights on condition factor and weight- length relationships on rainbow trout (oncorhynchus mykiss)

abstract the growth is a one of biological aspects of fishes and is a good index in order to determine of health of these population. the aim of this study was to investigate the effect of different color lights on condition factor and weight- length relationships (lwr) of rainbow trout. fertilized eggs of fish were kept under light conditions, 14h light and 10h dark for 5 months at seven lights color of white light(control), azure, blue, green, yellow, orange and red in farm aquaculture. after yolk sac absorption, weight and length of fry were measured by a digital scale and a caliper randomly. data was analyzed by anova, duncan and regression test. the results were showed that the highest and lowest condition factor was observed in yellow and green light respectively, but there wasn't significant different between treatment groups. there was seen significant association between weight- length relationships in different lights. growth pattern in often lights was isometric in different days. in some of lights, growth pattern was negative allometric. on the base of data of this study, it was concluded that different light can cause similar changes in weight and length of fish. in other words, rainbow trout can growth in different light proportionately.