Report of parasites in Corydoras Julii (Steindachner, 1906) and Corydoras punctatus (Bloch, 1794) (Siluriformes: Callichthydae) in ornamental fish stocking sites in the Belén area, Loreto-Peru

Abstract

In the present work, parasites, parasite indices and Sorensen's indices were determined in Corydoras julii and Corydoras punctatus. The work was carried out between February-July 2018 at the Hydrobiology Laboratory (FCB-UNAP). A total of 60 fish between both species (1.20 g and 1.97 g weight and length from 2 cm to 4.6 cm) provided by collectors from the area of Belén, Loreto-Peru were analysed. The fish were analysed by sacrificing them with a stylet at the level of the cephalic region until death, the external and internal organs were separated to be observed for parasites, which were placed separately on slides to be identified. The species Corydoras julii was infected by metacercariae of the genus Tylodelphys, larval and adult nematodes of the species Procamallanus (Spirocamallanus) pintoi, gill monogeneans of the genus Philocorydoras and Gyrodactylus. In Corydoras punctatus metacercariae of the genus Tylodelphys and nematode larvae were found. In relation to Corydoras julii and Corydoras punctatus a prevalence of 50% and 96.6% was obtained, with intensities of 6735, 1250 metacercariae of the genus Tylodelphys respectively. A positive correlation was obtained in relation to the condition factor of C. punctatus with parasite abundance (p < 0.05), while no correlation was obtained in Corydoras julii (p > 0.05). The qualitative and quantitative parasitic fauna of both fish species were compared, obtaining a similarity of 57% and 35% respectively.