Neogobius bathybius is a species of gobyendemic to the Caspian Sea, where it occurs in depths down to 200 metres (660 ft). It is strictly confined to the brackish-water basin and does not enter fresh waters. It can grow up to a length of 25 centimetres (9.8 in) TL.[1]
^Neilson M.E., Stepien C.A. (2009) Escape from the Ponto-Caspian: Evolution and biogeography of an endemic goby species flock (Benthophilinae: Gobiidae: Teleostei). Molecular Phylogenetics and Evolution, 52(1): 84-102.[1]