Abstract
Knowledge of the historical occurrence of the endangered cyprinid fish species, Eupallasella percnurus (Pall.), in today's Kujawsko-Pomorskie Voivodeship in Poland is sparse. However, a total of nine sites inhabited by this species had been identified by the end of the twentieth century, but only one of theses had survived into the early 2000s. The largest field inventory to date of this area was undertaken from 2005 to 2011 and nine new sites were recorded. Most of the newly discovered sites inhabited by E. percnurus are located in the Dobrzyńskie Lake District mesoregion, which is where this species has occurred in the past. Four of these sites have been designated as vulnerable and two as critically threatened. Immediate active protection measures are necessary to preserve E. percnurus at the two existing sites in the Special Protected Area PLH040013 "Cyprianka".