Serpulid patch reefs of Galeolaria hystrix Mörch, 1863 were found in water depths of 9–16 m in Big Glory Bay, Paterson Inlet, Stewart Island, and here we report preliminary studies of these important habitat‐formers. This is the first observation of this species in subtidal patch reefs; 114 reefs were noted in a survey of 28 000 m 2 . Most reefs were 1–5 m in diameter, and up to 1.5 m high. Up to 65% of the serpulid tubes were...