# Bluefin tuna's body stays warm but its heart does not Unlike most other fish, bluefin tuna can maintain a core body temperature of 25–33 °C (77–91 °F), in water as cold as 6 °C (43 °F). However, their heart stays cold. --- Source: [ScienceDaily](https://www.sciencedaily.com/releases/2015/02/150205083040.htm)