Mesogobius nonultimus, or the Caspian toad goby, is one of the species of gobiid fish endemic to the brackish-waters Caspian Sea (lake).

It will grow up to a length of 17.4 cm.

[1] It has been recorded from Turkmenistan, Daghestan, Azerbaijan and Iran, and is probably found throughout the lake, in the coastal zone down to 50 m depth.

[2][1] Its sister taxon in the Black Sea basin is Mesogobius batrachocephalus.

This Gobiidae-related article is a stub.