New records are given of the occurrence of the warm-water barnacle Solidobalanus fallax in Britain and Europe. This barnacle is not found on rocks or stones, but settles on biological substrata, including algae, cnidarians, bivalves, gastropods and crustaceans. It also settles on plastic bags and nets, plastic-coated objects such as crab and lobster pots and octopus pots made of ceramic or plastic.With one exception the species was unrecorded in Europe before 1980; it may have increased in abundance during recent years as a result of rising temperatures.The cyprid larvae, which can metamorphose on plastic Petri dishes, appear to be adapted to seek out low energy surfaces. One of the habitats colonized by S. fallax is the sea-fan Eunicella verrucosa, where it seems to have increased in recent years, possibly to the detriment of the cnidarian host. Solidobalanus fallax has the potential to be a serious pest of fish-farming structures to the south of Britain.
