Thymallus species are distinguished from other members of the salmon 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 body is also colourful; the dorsal surface is a dark purplish to bluish black or gray, grading to dark blue or silver gray on the flanks and gray or white on the belly.
The body is further decorated with a smattering of small dark spots; these are much more numerous in juveniles.

The longest of the graylings is the Arctic grayling,  T. arcticus, at a maximum length of 76 cm (30 in) and a maximum weight of 3.8 kg (8.4 lb).
T. thymallus, while somewhat shorter - 60 cm (24 in) - may weigh significantly more, 6.7 kg (15 lb).
The fishes of this genus may live for 18 years or more.
Thymallus species are distinguished from other members of the salmon 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 body is also colourful; the dorsal surface is a dark purplish to bluish black or gray, grading to dark blue or silver gray on the flanks and gray or white on the belly. The body is further decorated with a smattering of small dark spots; these are much more numerous in juveniles.
The longest of the graylings is the Arctic grayling,  T. arcticus, at a maximum length of 76 cm (30 in) and a maximum weight of 3.8 kg (8.4 lb). T. thymallus, while somewhat shorter - 60 cm (24 in) - may weigh significantly more, 6.7 kg (15 lb). The fishes of this genus may live for 18 years or more.
Thymallus