In this study, we conducted a unique survey of marine ornamental fishes appearing in UK retail stores, as well as a review of government trade statistics, with the aim to significantly strengthen the evidence‐base in support of future management initiatives. Fifty marine aquarium retailers were visited. A total of 380 marine aquarium fish species (4926 individuals), from 48 families were recorded with the largest proportion of individuals belonging to the families Pomacentridae, Acanthuridae, Apogonidae, Labridae, Pomacanthidae, Gobiidae and Labridae. The majority of fishes for sale (91% of species) originated from the Indo‐Pacific Ocean, with only a small number (9% of species) derived from the Atlantic Ocean. However, exact sources of individual species were unclear and poorly documented. Government trade statistics revealed that the ornamental reef‐fish trade in the UK grew markedly between 1996 and 2008 with a rapid acceleration in 2003–2004. However, imports have declined since 2008 and amounted to less than 305,000 kg in 2017 with an economic value of UK £3 million (c. US $3.8). Recent trade data (2017) identify Indonesia, USA, Philippines and the Maldives as the most important countries in terms of imports to the UK. The UK is an important exporter of wild‐caught fishes via trans‐shipment, but also production of tank‐reared animals. Several species observed for sale in the UK have been designated by the IUCN and CITES as being of conservation concern, although all these animals are thought to have been captive‐reared.