The purpose of this study was to determine the effects of replacing fish meal with red lentil meal (RLM) as an alternative plant protein source in diets for juvenile rainbow trout (10.14±0.04 g mean initial weight) on growth performance and amino acid composition of fish. Four iso-nitrogenous and iso-lipidic experimental diets were prepared to include 15% (RLM15), 20% (RLM20) and 25% (RLM25) of fish meal