Nodular coccidiosis in the gut of the tench, Tinca tinca L.

Abstract. In the intestinal epithelium of 3–5-summer old tench, Tinca tinca L., an unknown Eimeria sp. developing white, pinhead-sized nodules was found. Oocysts were shed in a non-sporulated state, but at 20°C in tap water they completed sporulation and resembled Eimeria subepithelialis , a parasite of common carp. During the period of examination, in April and May, only young oocysts and gamogonic stages developing in the epithelium of the mucosa were detected. Despite the morphological similarities and nodular occurrence there are significant differences between the nodular coccidiosis of the tench and common carp.