Novel fish-polychaete interactions, including the description of a unique partnership between a frogfish and a sabellid worm

Coral reefs host diverse ecological interactions, including a recently documented novel association between reef blennies and gobies and the species of Spirobranchus (Polychaeta, Serpulidae) commonly known as Christmas tree worms. We extend these records by adding Ecsenius bandanus Springer, 1971 to Spirobranchus-associated blennies. Furthermore, we report a previously unrecorded interaction between the frogfish Antennarius pictus (Shaw, 1794) and a species of Sabellidae likely belonging to Sabellastarte, two widely-distributed Indo-Pacific species. The frogfish directly approached the sabellid passing a pectoral fin through its extended radioles without triggering the worm’s typical withdrawal response, and then settled beside it while extending its lure for feeding. This behavior may confer enhanced camouflage and feeding advantages to the frogfish and potential protective or energetic benefits to the worm. Further research is needed to assess its prevalence and ecological significance across Indo-Pacific reefs.