The complex of chars composed of Arctic char (S. alpinus), Dolly Varden (S. malma) and bull trout (S. confluentus) is a closely related group and difficult to distinguish from external characteristics. Due to past misidentification of species in various locales and lack of scientific knowledge, much of the available literature on these species is either misleading or incorrect, and there is still some disagreement among scientists on their distribution.

The Dolly Varden and bull trout can generally be distinguished by their size and habitat. The Dolly Varden is usually a coastal species whereas the larger bull trout is found inland in large, cold rivers and lakes draining high, mountainous areas. A greater problem arises in trying to separate Dolly Varden from Arctic char. Much published information on the distribution of these species is incorrect and often presupposed that only one species occurred in areas or rivers where it is now believed both species may occur. The two are outwardly almost identical in every respect and to complicate matters, significant variations occurs in both species. The spots on the Dolly Varden are usually smaller than the pupil of the eye, while on the Arctic char they are larger than the pupil. When returning from the sea both species are silvery and lack spots. Arctic char on the average have more gill rakers on the first gill arch (25-30 as opposed to 21-22 in the Dolly Varden) and more pyloric caeca (40-45 as opposed to about 30 in Dolly Varden), but fish with intermediate counts (i.e., 23 or 24 gill rakers and 35 pyloric caeca) are not at all uncommon in either species.

Fish that don�t clearly �fit the pattern� will almost certainly have to be examined in a laboratory to determine their identity. IGFA recommends that all potential record chars that cannot be positively identified by external characteristics be frozen in case further study is needed.