Oligotherms are aquatic organisms that are stenotopic to cool water temperatures, usually within the range of 15–20 °C. These animals are well-suited to thrive in cold, stable environments where they can maintain an optimal body temperature for their metabolic processes.
Oligotherms are often found in deep-sea habitats such as the Antarctic continental shelf, where cold temperatures prevail throughout the year. Well-known examples include certain fish species like Arctic char and Atlantic salmon, as well as some deep-sea corals.