- 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 may form a spectacular view for any diver lucky enough to come across one. Like other sea fans 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 there are frequent observations below 50 meters depth. Like most other corals, it prefers current exposed locations, usually on rocky walls or steep slopes.
This is a well known species all over the North Atlantic Ocean.