A diverse fish assemblage is described from the uppermost Viséan (Mississippian, Carboniferous) of the Verkhnyaya Kardailovka section, South Urals, Russia. The uppermost Viséan (Mississippian, Carboniferous) of the Verkhnyaya Kardailovka section in the South Urals, Russia, has revealed a diverse fish assemblage. This section is particularly notable for housing the first occurrence of the conodont L. ziegleri, which serves as a significant marker for the proposed new level representing the boundary between the Viséan and Serpukhovian stages. The assemblage comes from several horizons in the carbonate sequence and includes 13 taxa of various chondrichthyans such as falcatid and symmoriid symmoriiformes, a phoebodontiform, squatinactiforms, euselachians, euchondrocephalians, and rare actinopterygians. Two new species, the symmoriiform Denaea patula and squatinactiform Squatinactis multicuspidatus, are described based on numerous teeth. The stratigraphic and geographical distribution of taxa included in the assemblage is discussed. The richest Viséan–Serpukhovian assemblages from different regions of the world are analyzed.