- Kingdom: Animalia
- Phylum: Cnidaria
- Class: Anthozoa
- Subclass: Hexacorallia
- Order: Alcyonacea
- Family: Paragorgiidae
- Scientific name: Paragorgia arborea
- Norwegian: sjøtre
This is a white, pink, red or sometimes deep orange sea fan. Reaching a height of as much as 6 meters, they form a spectacular view for any diver lucky enough to come across one. As all most other members of Hexacorallia, each polyp has eight tentacles - in contrast to the stony corals. The colony is often inhabited by Gorgon's heads.
This coral is common on depths between 200 and 1300 meters along the entire Norwegian coast. In the sheltered Norwegian fjords with much nutrition and little light due to poor visibility it can be found already at 40 meters depth. It is not unusual to find P. arborea in the neighborhood of reefs build by the stony coral L. pertusa. Like most other corals it prefers current exposed locations.
This is a well known species all over the North Atlantic Ocean.