List of British & Irish Fishes
What is a British species?
For this list, I have counted them as any fish, freshwater or saltwater, which have (or recently had) an established or seasonal population in the British Isles and surrounding seas; this would include non-natives, migratory fishes, and those whose ranges are expanding, but would exclude dumped aquarium fishes with no breeding population. I have selected these species from either verified records or range mapping which predicts a high probability of occurrence. With rising sea surface temperatures bringing new species all the time, this is not a complete list, but presently, there are over 600 species listed above—making it the most accurate and comprehensive list of British & Irish fishes to-date.
Certain species included (such as most of the whitefishes, char, and some trout) are generally not recognised in British literature, but are still considered valid on Eschmeyer's Catalog of Fishes.
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Sonaghan & Gillaroo, valid species of trout, similar to Brown Trout. Georgia Wild Trout. (2016). Trout Species of Ireland | Georgia Wild Trout. [online] Available at: https://www.georgiawildtrout.com/trout-species-of-ireland. "Genetic investigation of ferox trout carried out extensively in Ireland (predominately Lough Melvin) (Ferguson & Mason, 1981; Hamilton et al., 1989; Ferguson, 1989; Ferguson & Taggart, 1991; Hynes et al., 1996) and Scotland (Duguid et al., 2006) found ferox trout represent an ancestral lineage of S. trutta, and ferox trout inhabiting Loch Melvin, Awe and Laggan are more closely related than S. trutta in the same lake. These important discoveries prompted the reclassification of ferox trout as S. ferox by the IUCN, alongside the benthic gillaroo S. stomachicus and the pelagic sonaghen S. nigripinnis (Freyhof & Kottelat, 2008). Importantly as gillaroo and songahen were classified on the IUCN red list as ‘Vulnerable’, ferox trout were categorised as ‘Data deficient’ a reflection on the lack of substantial published literature." Hughes, Martin Robert (2017) What makes a ferox? The drivers and consequences of alternative life history strategies in S. trutta. PhD thesis. University of Glasgow. Available at: https://theses.gla.ac.uk/8280/1/2017HughesPhD.pdf
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The lesser known Salvelinus (Char) species which inhabit the British Isles. Many of which have been known to science for over a century, and more recently (1997) were evidenced to reside here. Salvelinus alpinus is no longer valid as of 2023, so is omitted from this list. Adams & Maitland (2007) believes the evidence for there being 15 British Char species as opposed to one could be better, but that they should continue to be considered individual species until wider samples have been taken that will settle which are distinct and which are synonyms of Arctic Char. Most authorities agree they belong to a species complex (either distinct morphs of Arctic Char, or distinct stem species of Arctic Char). IUCN has also reviewed these species in 2023, and as of 2025, they are valid species according to Eschmeyer's Catalog. Kottelat, M., 1997. European freshwater fishes. An heuristic checklist of the freshwater fishes of Europe (exclusive of former USSR), with an introduction for non-systematists and comments on nomenclature and conservation. Biologia, Bratislava. Kottelat, M. and J. Freyhof, 2007. Handbook of European freshwater fishes. Publications Kottelat, Cornol and Freyhof, Berlin. Maitland, P.S. et al. (2006) ‘The status of Arctic Charr Salvelinus alpinus in Britain and Ireland’, Ecology of Freshwater Fish, 16(1), pp. 6–19. doi:10.1111/j.1600-0633.2006.00167.x. Adams, C.E. and Maitland, P.S. (2006) ‘Arctic charr in Britain and Ireland – 15 species or one?’, Ecology of Freshwater Fish, 16(1), pp. 20–28. doi:10.1111/j.1600-0633.2006.00179.x.
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Cornish Sucker and Shore Clingfish are two distinct species, citing morphological evidence in 2002, and molecular evidence in 2017; with Shore Clingfish likely to be absent in Britain. HENRIQUES, M., LOURENCO, R., ALMADA, F., CALADO, G., GONCALVES, D., GUILLEMAUD, T., CANCELA, M.L. and ALMADA, V.C. (2002). A revision of the status of Lepadogaster lepadogaster (Teleostei: Gobiesocidae): sympatric subspecies or a long misunderstood blend of species? Biological Journal of the Linnean Society, 76(3), pp.327–338. doi:https://doi.org/10.1046/j.1095-8312.2002.00067.x. Wagner, M., Bračun, S., Kovačić, M., Iglésias, S., Sellos, D., Stamatis Zogaris and Koblmüller, S. (2017). Lepadogaster purpurea (Actinopterygii: Gobiesociformes: Gobiesocidae) from the eastern Mediterranean Sea: Significantly extended distribution range. Acta Ichthyologica Et Piscatoria, 47(4), pp.417–421. doi:https://doi.org/10.3750/aiep/02244.
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Phylogenetic changes you might not be familiar with: Sand Lances belong in the same Order (Labriformes) as the Wrasses; Grey Mullets are resolved in the same Order (Blenniformes) as True Blennies and Clingfish; Yarrell’s Blenny, Viviparous Blenny, Snakblennies & Butterfish are in the same Order (Perciformes) as Perch, Gurnard, and Sculpins, with no relation to the suborder of true blenny families (Blennioidei) or any of the Blenniformes; the suborders Tetraodontoidei (Puffers/Triggers/Molas) and Lophiodei (Anglerfish) have turned out to be sister lineages that belong within the Order Acanthuriformes, the Bream and allies. Near, T.J. and Thacker, C.E. (2024). Phylogenetic Classification of Living and Fossil Ray-Finned Fishes (Actinopterygii). Bullletin of the Peabody Museum of Natural History/Bulletin - Peabody Museum of Natural History, 65(1). doi:https://doi.org/10.3374/014.065.0101.
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“Genetic examination of bullheads from England confirmed the presence of Cottus perifretum, not Cottus gobio as traditionally listed in all UK literature and legislation. Native English bullhead is currently protected under Annex II of the European Commission Habitats Directive 92/43/EEC, based on the historic assumption that the species present is C. gobio.” Pickett, J. and Everard, M. (2025). The Bullhead in Britain: a small fish with an identity problem. British Wildlife 36.4, pp.266–271. McLeish, J. Non-native Bullhead in Scotland: Molecular and Morphological Identification and Parasite Links with Native Fauna. (Thesis). Edinburgh Napier University. Retrieved from http://researchrepository.napier.ac.uk/Output/1253308
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The Gobiformes in the British Isles are split into two families, the Typical Gobies (Gobiiae), and more recently, the Estuarine Gobies & Allies (Oxudericidae), which are actually closer in relation to Mudskippers than they are the Typical Gobies. Agorreta, A., San Mauro, D., Schliewen, U., Van Tassell, J.L., Kovačić, M., Zardoya, R. and Rüber, L. (2013). Molecular phylogenetics of Gobioidei and phylogenetic placement of European gobies. Molecular Phylogenetics and Evolution, 69(3), pp.619–633. doi:https://doi.org/10.1016/j.ympev.2013.07.017. Thacker, C.E. (2015). Biogeography of goby lineages (Gobiiformes: Gobioidei): origin, invasions and extinction throughout the Cenozoic. 42(9), pp.1615–1625. doi:https://doi.org/10.1111/jbi.12545. Gut, C., Vukić, J., Šanda, R., Moritz, T. and Reichenbacher, B. (2020). Identification of past and present gobies: distinguishing Gobius and Pomatoschistus (Teleostei: Gobioidei) species using characters of otoliths, meristics and body morphometry. Contributions to Zoology, 89(3), pp.282–323. doi:https://doi.org/10.1163/18759866-bja10002.
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Once considered as ‘Common skate’ (Dipturus batis), this has now been split into two species, Blue Skate (D. batis) and Flapper Skate (D. intermedius). Last, P., Weigmann, S. and Yang, L. (2016). Changes to the nomenclature of the skates (Chondrichthyes: Rajiformes).Bache-Jeffreys, M., de Moraes, B.L.C., Ball, R.E., Menezes, G., Pálsson, J., Pampoulie, C., Stevens, J.R. and Griffiths, A.M. (2021). Resolving the spatial distributions of Dipturus intermedius and Dipturus batis—the two taxa formerly known as the ‘common skate’. Environmental Biology of Fishes, 104(8), pp.923–936. doi:https://doi.org/10.1007/s10641-021-01122-7.
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Broad genetic testing revealed Smooth-hound, even the ones which looked identical to Mustelus mustelus (Common SH) in British waters, were in fact M. asteris (Starry SH). Farrell, E.D., Clarke, M.W. and Mariani, S. (2009). A simple genetic identification method for Northeast Atlantic smoothhound sharks (Mustelus spp.). ICES Journal of Marine Science, 66(3), pp.561–565. doi:https://doi.org/10.1093/icesjms/fsn218.Small, J. (2021). Starry Smooth-hound (Mustelus asterias). Inshore Fisheries and Conservation Authority.
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"The closest confirmed report was of a female [Great] White Shark, captured in 1977 in the northern Bay of Biscay – 168 miles off Land’s End, Cornwall." Conditions in Britain for this species are becoming increasingly favourable. The Shark Trust. (n.d.). British Sharks. [online] Available at: https://www.sharktrust.org/pages/faqs/category/british-sharks.
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The domestication of koi has a long and complex history which needs further investigation, but presently, certain regions of the world appear to have a different ancestral species for their koi. Much of the world’s koi, specifically western Europe, are attributed to the Amur carp (Cyprinus rubrofuscus), based on meristics and some genetic evidence. Craig, J.F. (2015). Freshwater Fisheries Ecology. Wiley-Blackwell. p. 297. ISBN 978-1-118-39442-7.
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Nigorobuna is currently not a recognised species or subspecies. Different authorities cited them as either Carassius auratus grandoculis, Carassius buergeri grandoculis, or Carassius grandoculis, but all have since been synonymised with Carassius auratus (Brown Goldfish). Eschmeyer’s Catalog of Fishes. (n.d.). Species that contain: Carassius. [online] Available at: https://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp.
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Dactylopteridae, a family which contains the Flying Gurnards, according to Near & Thacker, 2024, belong to a different order (the Syngnathiformes) to the other gurnard family (Triglidae) which are in the Perciformes. Near, T.J. and Thacker, C.E. (2024). Phylogenetic Classification of Living and Fossil Ray-Finned Fishes (Actinopterygii). Bullletin of the Peabody Museum of Natural History/Bulletin - Peabody Museum of Natural History, 65(1). doi:https://doi.org/10.3374/014.065.0101.
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The Houting (Coregonus oxyrinchus) was once thought extinct, but in 2023, genetic analysis revealed them to be the same as the Common whitefish (Coregonus lavaretus). It's unclear which taxon name is being used, and which is now inactive. Kroes, R., Winkel, Y., Johannes, E.E. van Loon, Loader, S.P., Maclaine, J.S., P.F.M. Verdonschot and van (2023). Phylogenetic analysis of museum specimens of houting Coregonus oxyrinchus shows the need for a revision of its extinct status. BMC Ecology and Evolution, 23(1). doi:https://doi.org/10.1186/s12862-023-02161-7. Amsterdam, U. of (2023). Officially extinct fish is alive and well, according to DNA analyses. [online] Phys.org. Available at: https://phys.org/news/2023-10-extinct-fish-alive-dna-analyses.html.
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Killarney Shad are a young species which stemmed from landlocked Twaite Shad in Lough Leane, which arrived 10,000–20,000 years ago. Once considered a subspecies of the Twaite Shad, they are now considered their own species. Coscia, I. et al. (2013) ‘A species-to-be? the genetic status and colonization history of the critically endangered Killarney Shad’, Molecular Phylogenetics and Evolution, 69(3), pp. 1190–1195. doi:10.1016/j.ympev.2013.07.029.
