Remains of decapod crustaceans of the family Alpheidae Rafinesque, 1815 and bony fish of the family Gobiidae Bonaparte, 1832 co-occur at a number of localities in the Korytnica Basin (Holy Cross Mountains) and in a newly exposed section along a stream near Niskowa (Outer Carpathians), both in southern Poland. These remains (alpheid major right-sided cheliped tips and gobiid otoliths) are interpreted as documenting a commensal partnership that existed in the shallowest zones of the middle Miocene Fore-Carpathian Basin in southern Poland under environmental conditions that must have been comparable to those of the present-day tropical/ subtropical Indo-West Pacific and Caribbean.