Abstract

The Brazilian aquaculture stands out due to the climate and water availability, and grows along with the world fish production, due especially to the human population growth. The Piaractusspp. shows great participation in production due to the high economic value and productive performance, and because species of the genus are native from South America, including Brazil. Fish are susceptible to parasitizing infection by Piscinoodinium pillulare, a protozoa that causes a disease known as “rust disease”, even more at high population densities and stressful circunstances.An outbreak was observed in a semi intensive aquaculture farming property of Piaractus spp. for preservation, and without any commercial interest, in the municipality of Jataí, Goiás, Brazil, where the main characteristics were: dying fish on the water surface; petechiae in the ventral region of the body, especially in the abdomen; ulcers in the cranial portion; inappetence; and high mortality rates. Three specimens of P. brachypomus were captured and a scraped was performed on the body surface and gills and subjected to microscopic analysis. After microscopic analysis, P. pillulare was observed in slides of all samples. The diagnose was based only on the visualization of P. pillulare trophons (protozoa) in the skin and gills of the fish. The populational and climate conditions that P. brachypomus were exposed at Brazilian Cerrado are equivalent with those required to lead fish to stressful conditions and thus, make them susceptible to parasites infections, such as P. pillulare.

Keywords

disease, fishes, gills, parasitism, pisciculture, skin