Abstract
Out of 58 live tilapia fish, five Oreochromis niloticus were found to be naturally infected with Henneguya suprabranchiae (8.62%). Such infection was recorded only during winter season from Bahr Shebin, a tributary of the River Nile at Menoufia Governorate, Nile Delta, Egypt. Based on the structure and measurements of fresh spores, this parasite was identified as H. suprabranchiae. Spores are oval in shape and they measure 15 (13-16)x5 (4-6) mu m length by width. It has two polar capsules inside and they measure 4 (5-7)x(2-3) mu m length by width. Each polar capsule has spirally coiled (7-9 turns) polar filament. The plasmodia as well as all other parasitic stages were described using light and transmission electron microscopy and discussed regarding to those of other fish hosts especially those of Africa.