Studies regarding parasite fauna in farmed fish are of great relevance to lhe knowledge of the parasites species. allowing interference in their proliferation in order to avoid epizooties and consequently. economical losses, This study was designed to investigate the prevalence and intensity of parasites in fry Arapaima gigas maintained in ponds of a semi-intensive fish farm in Amazonas State, Brazil. On necropsy, 96,0% of A. gigas were found parasitized by Dawestrema cycloancistrioides. Dawestrema cycloancistrioides (Monogenoidea). Trichodina sp., Ichthyobodo sp. (Protozoa). Camallamus tridentatus, Terranova serrata, Goezia spinulosa (Nematoda) and Argulidae. However, D. cycloancistrium. D, cycloancistrioides and Trichodina fariai were the parasites of' greatest intensity. This study is the first to report parasitic infections in farmed A. gigas and the results indicated a high rate of infection that might lead to important changes in the health of the hosts
