Thymallus species are distinguished from other members of the salmonid family by their larger scales, their small mouths with teeth on the maxillary bone, and most striking of all, their showy, sail-like dorsal fins.

This fin is longer in males and highly colourful, with spots of red, orange, purple or green.

The grayling species, typically for salmonids, spawn in rivers and do not guard their brood, although they do conceal their eggs in silt.

[8] As they are highly sensitive to changes in water quality, Thymallus fishes may be considered indicator species; T. arcticus has largely disappeared from the Great Lakes Basin.

Due to their agreeable taste and attractive form, the grayling species are valued as food and game fishes, and they are occasionally seen in public aquaria.