Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes. It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefishes, graylings, taimens and lenoks, which are collectively known as the salmonids ("salmon-like fish"). The Atlantic salmon (Salmo salar), whose Latin name became that of its genus Salmo, also derives the family and order names.
Salmonids have a relatively primitive appearance among the teleost fish, with the pelvic fins being placed far back, and an adipose fin towards the rear of the back. They are slender fish, with rounded scales and forked tails. Their mouths contain a single row of sharp teeth. Although the smallest species is just 13 cm (5.1 in) long as an adult, most are much larger, with the largest reaching 2 m (6 ft 7 in).
All salmonids spawn in fresh water, but in many cases, the fish spend most of their lives at sea, returning to the rivers only to reproduce. This lifecycle is described as anadromous. They are carnivorous predators, feeding on small crustaceans, aquatic insects and smaller fish.