Which scorpaeniform fishes can live in freshwater habitats?

Scorpaeniform fishes are primarily marine, but several species have successfully adapted to freshwater environments, particularly in the Northern Hemisphere.12

The primary group of scorpaeniforms found in freshwater are the sculpins (family Cottidae), which are widely distributed across North America, Europe, and Asia. Notable examples include:23

• Miller’s thumb (Cottus gobio): A common species found in European lakes and rivers.23
• Lake Baikal species: Russia's Lake Baikal hosts endemic sculpins such as C. kneri and C. kessleri.2

In addition to the Cottidae, two closely related families are also found in freshwater, specifically within Lake Baikal:2

• Cottocomephoridae: A diverse family containing eight genera and numerous species that have adapted to various depths and habitats within the lake.2
• Comephoridae: Known as Baikal cods, this family includes two pelagic species, Comephorus baicalensis and C. dybowskii, the latter of which can inhabit depths of up to 1,000 metres.2

These freshwater scorpaeniforms exhibit diverse behaviors, ranging from benthic (bottom-dwelling) lifestyles to pelagic existence, and have evolved to exploit various ecological niches in inland waters.2