Tubularia indivisa colour por Alexander Semenov

Tubularia indivisa, commonly known as the oaten pipes hydroid, is a species of large hydroid native to the northeastern Atlantic Ocean, the North Sea, Norwegian Sea, and the English Channel. The conical solitary polyps are found on dull yellow unbranched stems that reach 10 to 15 cm (3.9 to 5.9 in) in height with a diameter of 1.5 cm (0.59 in). They may be fused to a small number of other individual stems at their bases. The pinkish to red polyps resemble flowers, having two concentric rings of tentacles, with the outer rings being paler and longer than the inner ring. At the center is a pale pink gonotheca. They are preyed upon by nudibranchs.