Astyanax bimaculatus is a host to various parasites that colonize different parts of the body. Creptotrema dissimilis is a species of trematode (flatworm) that inhabits the intestines. Magnivitellinum simplex, another intestinal trematode, was first described from A. bimaculatus in Brazil. Parasitic isopod Livoneca lazzari was also first described from A. bimaculatus, this time from the gill cavity. The parasites most likely to infect A. bimaculatus come from Monogenea, a class of parasitic flatworms, and infections are more common during the rainy seasons.
