The Don tadpole-goby (Benthophilus durrelli) is a species of goby widespread in the basin of the Sea of Azov, specifically in the lower Don River and Tsimlyansk Reservoir. This species is found in rivers, reservoirs and river mouths, but is not known to enter seas. It is introduced and invasive upstream the Volga River, e.g. the Kuibyshev Reservoir. This fish can reach a length of 6.6 centimetres (2.6 in) SL. Life span is about one year.