According to the result of a pilot phylogenetic analysis, the freshwater Mesocottus is a sister lineage to the Cottus clade.
The Timavo sculpin, Cottus scaturigo, is a freshwater species of fish that is found only in Timavo Spring in Italy.
Prickly sculpin (Cottus asper) and Hitch (Lavinia exilicauda) are also present, but are relatively scarce.