Abstract The present study objectified to evaluate the trophic relationships and possible aggressive mimicry involving Carnegiella strigata, marthae Gnathocharax steindachneri, in lowland forest streams. Samplings occurred November 2002, March August 2003 Amanã Sustainable Development Reserve (ASDR). total of 943 fish was caught, being 79.43% C. marthae, 3.18% strigata 17.39% G. steindachneri. ...