Rainbow trout is an intensively cultured species because of their more cultivable character than brown trout. Culture of brown trout could not be expanded due to low growth performance of brown trout compared to rainbow trout. This experiment was conducted in a commercial trout farm, Aegean area (Turkey). Growth performances and survivals of rainbow and brown trouts from fry to fingerling was observed for 155 days. Growth performances, feed conversion rates (FCR) and survivals were determined. Initial weights of rainbow and brown trouts were 0.1 +/- 0.01 g. Final weights were 26.5 +/- 5.19 and 12.97 +/- 2.74 g, respectively at the end of the experiment. Survival and FCR of rainbow and brown trouts were 83.9, 80 and 0.59, 0.61% respectively. As a result, there is a similarity between these two trout species in point of survivals and FCR's although, growth performance was obviously better than brown trout in early development of rainbow trout.