Alex Mustard,Alex Mustard / A nudibranch (Flabellina nobilis) feeding on a solitary hydroid (Tubularia indivisa), note how the hydroid is bent back as it is pulled into the nudibranch's mouth. Gulen, Bergen, Norway. North East A...

Andy Jackson / 2020VISION / Oaten pipe hydroid group (Tubularia indivisa), with Jewel anemones (Corynactis viridis), Muckle Flugga, Shetland, Scotland, UK, June.

Alex Mustard / Nudibranch (Flabellina nobilis) feeding on a solitary hydroid (Tubularia indivisa) and laying eggs. Gulen, Bergen, Norway. North East Atlantic Ocean.

Alex Mustard / A nudibranch (Flabellina lineata) feeding on a solitary hydroid (Tubularia indivisa). Gulen, Bergen, Norway. North East Atlantic Ocean.

Solvin Zankl / Oaten pipes hydroid (Tubularia indivisa), Atlantic Ocean, North West Norway

Solvin Zankl / Oaten pipes hydroid (Tubularia indivisa), Atlantic Ocean, North West Norway

Solvin Zankl / Oaten pipes hydroid (Tubularia indivisa), Atlantic Ocean, North West Norway

Linda Pitkin / 2020VISION / Oaten pipes hydroid (Tubularia indivisa), St Abbs (St Abbs and Eyemouth Voluntary Marine Reserve), Berwickshire, Scotland, UK, October 2011

Sue Daly / Oaten Pipe Hydroid (Tubularia indivisa). Channel Islands, UK, July.

Sue Daly / Oaten Pipe Hydroid (Tubularia indivisa). Channel Islands, UK, August.

Sue Daly / Oatenpipe hydroids (Tubularia indivisa) underwater, Channel Isles, UK, June

Sue Daly / Oaten pipe hydroid {Tubularia indivisa} Jersey, Channel Isles, UK Schockland wreck