Zootechnic Performences Compared between Freshwater Rotifer (Brachionus calyciflorus) and Nauplii Artemia salina in River Perch Perca fluviatilis L. In able to improve survival rate and growth in perch Perca fluviatilis larvae which are very small at hatching stage, larvae are submitted two days after hatching to different live food: fresh water Rotifer Brachionus calyciflorus and nauplii of Artemia salina.Thus, to avoid the big mortality which occure because of manipulation of larvae, eggs in eye stage were shared in two duplicated groups and feeding of larvae started two days after hatching. Mortality was significant in the two groups from the day 7. However, at the end of the experiment, the group fed Rotifer at the begining of feeding, exhibited the best homogeneity, the best survival and the best food convertion ratio. So, this experiment has shown clearly that at hatching time, all perch larvae are not able to ingest nauplii Artemia. It is necessary to mix their starter food with Rotifer.