In this study, the effects of dandelion (Taraxacum qfficinale) root (Root(()(Ex)())), leaf (Leaf(()(Ex)())), and flower (Flower(()(Ex)())) extract on growth performance, feed utilization, body composition, and hematological blood parameters on fingerling rainbow trout (Oncorhynchus mykiss) were investigated. This intendment, a commercial trout feed was supplemented with dandelion root, leaf, and flower extracts. In the study, 360 fingerling rainbow trout (20.00 +/- 1.025 g and 11.77 +/- 0.880 cm) were stocked in 12 tanks (30 individuals 80 L-1 tank) and fed for 90 days. To do this, four trial groups with three replications (Control (no extract); Root(()(Ex)()) 10 ml Kg(-1); Leaf(()(Ex)()) 10 ml kg(-1); Flower(()(Ex)()) 10 ml kg(-1)) were formed. The results showed that the supplementation of dandelion extract to the trout feed can have a significant effect on growth performance, body composition, and hematological blood parameters. Accordingly, the best final body weight (FBW), feed intake (FT), weight gain (WG), weight gain rate (WGR), specific growth rate (SGR), protein efficiency ratio (PER), protein deposit rate (PDR), and the lowest feed conversion ratio (FCR) were determined in Root n ) (P<0.05). Condition factor (CF), Viscerasomatic index (VSI), Hepatosomatic index (HSI), and survival rate (SR) were insignificance (P>0.05). As a result of muscle and liver proximate analyzes, Root(()(Ex)()) significantly increased crude protein and decreased crude lipid values compared to control (P<0.05). Hematological blood values in all extract groups were higher than the control and statistically significant (P<0.05). Depending on the results, it was concluded that dandelion root extract is more effective in terms of aquaculture, and there is no adverse effect in using it as an alternative additive in feeds as a hypolipidemic and growth-promoting additive.