Salvelinus alpinus, commonly known as the Arctic char, thrives in cold, clear waters of the Arctic, sub-Arctic, and alpine lakes. Notable for its variable coloration, it displays a vibrant mix of reds, browns, and greens, particularly during spawning. It's anadromous, migrating between freshwater and the ocean, and plays a crucial role in its ecosystem as both predator and prey.

Salvelinus alpinus, commonly known as the Arctic char, is natively found in the circumpolar regions. Its geographical distribution includes areas across the Arctic and sub-Arctic, spanning North America (particularly in Canada and Alaska), Europe (notably in Scandinavia and parts of the British Isles), and Asia (specifically in Siberia).

The Arctic char typically inhabits cold, oligotrophic lakes and rivers, often in remote, mountainous regions. These environments are characterized by clear, cold water with low nutrient levels. In some areas, they are found in coastal marine environments, particularly during certain life stages.

As a cold-water species, the Arctic char is well-adapted to life in low-temperature environments. It occupies various ecological niches based on life stage and region, including freshwater lakes, rivers, and brackish coastal waters. The species is known for its high degree of phenotypic plasticity, allowing it to adapt to different ecological conditions, which is reflected in the presence of both anadromous and landlocked populations.