| Nominal Species (n = 415) | Present allocation (n = 293) | Ref. |
|---|---|---|
| Oligocottus acuticeps Gilbert, 1896 | Clinocottus acuticeps | 26282 |
| Cottus aenaeus Mitchill, 1814 | Myoxocephalus aenaeus | 12965 |
| Cottus affinis Heckel, 1837 | Cottus gobio | 13696 |
| Crossias albomaculatus Schmidt, 1916 | Porocottus mednius | 43939 |
| Centridermichthys alcicornis Herzenstein, 1890 | Alcichthys elongatus | 58496 |
| Cottus aleuticus Gilbert, 1896 | Cottus aleuticus | 3814 |
| Crossias allisi Jordan & Starks, 1904 | Porocottus allisi | 26282 |
| Cottus amblystomopsis Schmidt, 1904 | Cottus amblystomopsis | 559 |
| Oligocottus analis Girard, 1858 | Clinocottus analis | 12965 |
| Thyriscus anoplus Gilbert & Burke, 1912 | Thyriscus anoplus | 6876 |
| Artediellus antilope Schmidt, 1937 | Artediellina antilope | 46206 |
| Artediellus aporosus Soldatov, 1922 | Artediellus aporosus | 46206 |
| Centridermichthys argenteus Döderlein, 1887 | Pseudoblennius argenteus | 40966 |
| Ochotskia armata Schmidt, 1916 | Icelus armatus | 46206 |
| Leptocottus armatus Girard, 1854 | Leptocottus armatus | 26282 |
| Cottus asper Richardson, 1836 | Cottus asper | 5723 |
| Cottus asperrimus Rutter, 1908 | Cottus asperrimus | 5723 |
| Radulinus asprellus Gilbert, 1890 | Radulinus asprellus | 26282 |
| Artediellus atlanticus Jordan & Evermann, 1898 | Artediellus atlanticus | 4698 |
| Cottus aturi Freyhof, Kottelat & Nolte, 2005 | Cottus aturi | 55856 |
| Artedielloides auriculatus Soldatov, 1922 | Artedielloides auriculatus | 27683 |
| Boreocottus axillaris Gill, 1859 | Myoxocephalus scorpioides | 50838 |
| Cottus baicalensis Dybowski, 1874 | Batrachocottus baicalensis | 33021 |
| Callionymus baikalensis Pallas, 1776 | Comephorus baikalensis | 1830 |
| Cottus baileyi Robins, 1961 | Cottus baileyi | 5723 |
| Cottus bairdii Girard, 1850 | Cottus bairdii | 1998 |
| Cottus bathybius Günther, 1878 | Zesticelus bathybius | 40966 |
| Triglops beani Gilbert, 1896 | Triglops pingelii | 7297 |
| Cottus beldingii Eigenmann & Eigenmann, 1891 | Cottus beldingii | 12965 |
| Potamocottus bendirei Bean, 1881 | Cottus bendirei | 50838 |
| Limnocottus bergianus Taliev, 1935 | Limnocottus bergianus | 26334 |
| Taurocottus bergii Soldatov & Pavlenko, 1915 | Taurocottus bergii | 46206 |
| Stelgistrum beringianum Gilbert & Burke, 1912 | Stelgistrum beringianum | 6876 |
| Cottus bicornis Reinhardt, 1840 | Icelus bicornis | 26282 |
| Archaulus biseriatus Gilbert & Burke, 1912 | Archistes biseriatus | 43939 |
| Aspicottus bison Girard, 1854 | Enophrys bison | 26282 |
| Cottus boleoides Girard, 1850 | Cottus cognatus | 54621 |
| Radulinus boleoides Gilbert, 1898 | Radulinus boleoides | 26282 |
| Icelinus borealis Gilbert, 1896 | Icelinus borealis | 26282 |
| Abyssocottus boulengeri Berg, 1906 | Cottinella boulengeri | 26282 |
| Porocottus bradfordi Rutter, 1898 | Porocottus mednius | 43939 |
| Cottus brandtii Steindachner, 1867 | Myoxocephalus brandtii | 26282 |
| Trichocottus brashnikovi Soldatov & Pavlenko, 1915 | Trichocottus brashnikovi | 43939 |
| Cottus bubalis Euphrasen, 1786 | Taurulus bubalis | 3397 |
| Icelinus burchami Evermann & Goldsborough, 1907 | Icelinus burchami | 26282 |
| Cottus caeruleomentum Kinziger, Raesly & Neely, 2000 | Cottus caeruleomentum | 37399 |
| Artediellus camchaticus Gilbert & Burke, 1912 | Artediellus camchaticus | 559 |
| Crossias camtschaticus Schmidt, 1916 | Porocottus camtschaticus | 33021 |
| Icelus canaliculatus Gilbert, 1896 | Icelus canaliculatus | 6793 |
| Potamocottus carolinae Gill, 1861 | Cottus carolinae | 12965 |
| Agonocottus cataphractus Pavlenko, 1910 | Icelus cataphractus | 26282 |
| Sigmistes caulias Rutter, 1898 | Sigmistes caulias | 26282 |
| Icelinus cavifrons Gilbert, 1890 | Icelinus cavifrons | 2850 |
| Podabrus centropomus Richardson, 1848 | Vellitor centropomus | 26282 |
| Cottus chamberlaini Evermann & Goldsborough, 1907 | Cottus cognatus | 1998 |
| Cottus chattahoochee Neely, Williams & Mayden, 2007 | Cottus chattahoochee | 72414 |
| Blennicottus clarki Evermann & Goldsborough, 1907 | Artediellus pacificus | 11366 |
| Cottus claviger Cuvier, 1829 | Enophrys diceraus | 50838 |
| Cottus cognatus Richardson, 1836 | Cottus cognatus | 10280 |
| Cottus comephoroides Berg, 1900 | Cottocomephorus inermis | 12480 |
| Stelgistrum concinnum Andriashev, 1935 | Stelgistrum concinnum | 43939 |
| Cottus confusus Bailey & Bond, 1963 | Cottus confusus | 5723 |
| Allartedius corallinus Hubbs, 1926 | Artedius corallinus | 12965 |
| Porocottus coronatus Yabe, 1992 | Porocottus coronatus | 34715 |
| Podabrus cottoides Richardson, 1848 | Pseudoblennius cottoides | 26282 |
| Ruscariops creaseri Hubbs, 1926 | Ruscarius creaseri | 12965 |
| Phasmatocottus ctenopterygius Bolin, 1936 | Phasmatocottus ctenopterygius | 559 |
| Cottus cyclophthalmus Sideleva, Kesminas & Zhidkov, 2022 | Cottus cyclophthalmus | 129290 |
| Cottus czerskii Berg, 1913 | Cottus czerskii | 26334 |
| Cottus decastrensis Kner, 1865 | Myoxocephalus stelleri | 58496 |
| Artedius delacyi Hubbs & Schultz, 1941 | Artedius lateralis | 10937 |
| Radulinopsis derjavini Soldatov & Lindberg, 1930 | Radulinopsis derjavini | 45347 |
| Radulinopsis derjugini Soldatov, 1930 | Radulinopsis derjavini | 45347 |
| Gymnocanthus detrisus Gilbert & Burke, 1912 | Gymnocanthus detrisus | 559 |
| Cottus diceraus Pallas, 1787 | Enophrys diceraus | 58462 |
| Stlengis distoechus Bolin, 1936 | Stlengis distoechus | 559 |
| Triglops dorothy Pietsch & Orr, 2006 | Triglops dorothy | 57076 |
| Cottus duranii Freyhof, Kottelat & Nolte, 2005 | Cottus duranii | 55856 |
| Comephorus dybowskii Korotneff, 1904 | Comephorus dybowskii | 12480 |
| Artediellus dydymovi Soldatov, 1915 | Artediellus dydymovi | 26282 |
| Cottus dzungaricus Kottelat, 2006 | Cottus dzungaricus | 57778 |
| Cottus echinatus Bailey & Bond, 1963 | Cottus echinatus | 3814 |
| Icelus ecornis Tsutsui & Yabe, 1996 | Icelus ecornis | 41299 |
| Antipodocottus elegans Fricke & Brunken, 1984 | Antipodocottus elegans | 7300 |
| Centridermichthys elegans Steindachner, 1881 | Bero elegans | 26282 |
| Abyssocottus elochini Taliev, 1955 | Abyssocottus elochini | 26334 |
| Centridermichthys elongatus Steindachner, 1881 | Alcichthys elongatus | 46206 |
| Oligocottus embryum Jordan & Starks, 1895 | Clinocottus embryum | 26282 |
| Ainocottus ensiger Jordan & Starks, 1904 | Myoxocephalus polyacanthocephalus | 10937 |
| Artediellus europaeus Knipowitsch, 1907 | Artediellus atlanticus | 93826 |
| Icelus euryops Bean, 1890 | Icelus euryops | 26282 |
| Bolinia euryptera Yabe, 1991 | Bolinia euryptera | 39612 |
| Cottus extensus Bailey & Bond, 1963 | Cottus extensus | 5723 |
| Trachidermus fasciatus Heckel, 1837 | Trachidermus fasciatus | 26763 |
| Artedius fenestralis Jordan & Gilbert, 1883 | Artedius fenestralis | 26282 |
| Cottus ferrugineus Bonaparte, 1846 | Cottus gobio | 55856 |
| Cottus ferrugineus Heckel & Kner, 1858 | Cottus gobio | 55856 |
| Icelinus filamentosus Gilbert, 1890 | Icelinus filamentosus | 6793 |
| Icelinus fimbriatus Gilbert, 1890 | Icelinus fimbriatus | 2850 |
| Elanura forficata Gilbert, 1896 | Triglops forficatus | 7297 |
| Cottus formosus Girard, 1851 | Cottus cognatus | 1998 |
| Cottus franklini Agassiz, 1850 | Cottus cognatus | 1998 |
| Artediellus fuscimentus Nelson, 1986 | Artediellus fuscimentus | 41299 |
| Abyssocottus fuscus Bogdanov, 2014 | Abyssocottus fuscus | 130169 |
| Antipodocottus galatheae Bolin, 1952 | Antipodocottus galatheae | 7300 |
| Gymnocanthus galeatus Bean, 1881 | Gymnocanthus galeatus | 6793 |
| Abyssocottus gibbosus Berg, 1906 | Abyssocottus gibbosus | 26334 |
| Abyssocottus gibbosus subulatus Dybowski, 1908 | Abyssocottus subulatus | 130169 |
| Hemilepidotus gilberti Jordan & Starks, 1904 | Hemilepidotus gilberti | 559 |
| Icelus gilberti Taranetz, 1936 | Icelus gilberti | 559 |
| Synchirus gilli Bean, 1890 | Synchirus gilli | 26282 |
| Cottus girardi (non Robins, 1961) | Cottus bairdii | 1998 |
| Cottus girardi Robins, 1961 | Cottus girardi | 5723 |
| Oligocottus globiceps Girard, 1858 | Clinocottus globiceps | 26282 |
| Cottus gobio Linnaeus, 1758 | Cottus gobio | 55856 |
| Cottus gobio haemusi (non Marinov & Dikov, 1986) | Cottus gobio | 59043 |
| Cottus gobio haemusi Marinov & Dikov, 1986 | Cottus haemusi | 59043 |
| Cottus gobio hispaniolensis (non Băcescu & Băcescu-Meşter, 1964) | Cottus gobio | 55856 |
| Cottus gobio hispaniolensis Băcescu & Băcescu-Meşter, 1964 | Cottus hispaniolensis | 55856 |
| Cottus gobio jaxartensis Berg, 1916 | Cottus gobio | 13696 |
| Cottus gobio macrostomus Jeitteles, 1863 | Cottus gobio | 55856 |
| Cottus gobio microcephalus (non Kessler, 1868) | Alpinocottus poecilopus | 55856 |
| Cottus gobio microcephalus Kessler, 1868 | Cottus koshewnikowi | 55856 |
| Cottus gobio milvensis (non Soldatov, 1924) | Cottus gobio | 55856 |
| Cottus gobio milvensis Soldatov, 1924 | Cottus koshewnikowi | 55856 |
| Cottus gobio pellegrini Băcescu & Băcescu-Meşter, 1964 | Cottus gobio | 13696 |
| Cottus gobio pellegrini Vladykov, 1931 | Cottus gobio | 13696 |
| Cottus gobio roseus Odenwall, 1927 | Cottus gobio | 13696 |
| Cottus godlewskii Dybowski, 1874 | Limnocottus godlewskii | 33021 |
| Limnocottus godlewskii bergi Dybowski, 1908 | Limnocottus godlewskii | 2058 |
| Abyssocottus godlewskii griseus Taliev, 1955 | Limnocottus griseus | 40966 |
| Artediellus gomojunovi Taranetz, 1933 | Artediellus gomojunovi | 6876 |
| Cottiusculus gonez Jordan & Starks, 1904 | Cottiusculus gonez | 559 |
| Procottus gotoi Sideleva, 2001 | Procottus gotoi | 53210 |
| Cottus gracilis Heckel, 1837 | Cottus cognatus | 1998 |
| Cottus gratzianowi Sideleva, Naseka & Zhidkov, 2015 | Cottus gratzianowi | 101366 |
| Uranidea greenei Gilbert & Culver, 1898 | Cottus greenei | 33021 |
| Cottocomephorus grewingki alexandrae Taliev, 1935 | Cottocomephorus alexandrae | 51998 |
| Cottus grewingkii Dybowski, 1874 | Cottocomephorus grewingkii | 2058 |
| Cottus groenlandicus Cuvier, 1829 | Myoxocephalus scorpius | 43939 |
| Cottopsis gulosus Girard, 1854 | Cottus gulosus | 26282 |
| Metacottus gurwicii Taliev, 1946 | Procottus gurwicii | 26282 |
| Cottus haitej Dybowski, 1869 | Mesocottus haitej | 26282 |
| Cottus hangiongensis Mori, 1930 | Cottus hangiongensis | 559 |
| Axyrias harringtoni Starks, 1896 | Artedius harringtoni | 26282 |
| Cottus hemilepidotus Tilesius, 1811 | Hemilepidotus hemilepidotus | 26282 |
| Asprocottus herzensteini Berg, 1906 | Asprocottus herzensteini | 130169 |
| Gymnocanthus herzensteini Jordan & Starks, 1904 | Gymnocanthus herzensteini | 559 |
| Asprocottus herzensteini abyssalis Taliev, 1955 | Asprocottus abyssalis | 130169 |
| Asprocottus herzensteini intermedius Taliev, 1955 | Asprocottus intermedius | 46206 |
| Asprocottus herzensteini parmiferus Taliev, 1955 | Asprocottus parmiferus | 26282 |
| Asprocottus herzensteini platycephalus Taliev, 1955 | Asprocottus platycephalus | 26282 |
| Cottus hexacornis Richardson, 1823 | Myoxocephalus quadricornis | 26282 |
| Leiocottus hirundo Girard, 1856 | Leiocottus hirundo | 2850 |
| Uranidea hoyi Putnam, 1876 | Cottus cognatus | 1998 |
| Cottus hubbsi (non Bailey & Dimick, 1949) | Cottus bairdii | 1998 |
| Cottus hubbsi Bailey & Dimick, 1949 | Cottus hubbsi | 54825 |
| Cottus humilis Bean, 1881 | Myoxocephalus jaok | 43939 |
| Cottus hypselurus Robins & Robison, 1985 | Cottus hypselurus | 3814 |
| Pegedictis ictalops Rafinesque, 1820 | Cottus bairdii | 93641 |
| Cottus immaculatus Kinziger & Wood, 2010 | Cottus immaculatus | 83416 |
| Myoxocephalus incitus Watanabe, 1958 | Myoxocephalus stelleri | 43239 |
| Cottus inermis Yakovlev, 1890 | Cottocomephorus inermis | 12480 |
| Artediellus ingens Nelson, 1986 | Artediellus ingens | 43939 |
| Cottus intermedius Temminck & Schlegel, 1843 | Gymnocanthus intermedius | 26282 |
| Furcina ishikawae Jordan & Starks, 1904 | Furcina ishikawae | 559 |
| Cottus jaok Cuvier, 1829 | Myoxocephalus jaok | 26282 |
| Icelinus japonicus Yabe, Tsumura & Katayama, 1980 | Icelinus japonicus | 559 |
| Porocottus japonicus Schmidt, 1935 | Porocottus japonicus | 34715 |
| Procottus jeittelesi bicolor Dybowski, 1908 | Procottus jeittelesii | 2058 |
| Procottus jeittelesi major Taliev, 1949 | Procottus major | 33021 |
| Procottus jeittelesi minor Taliev, 1946 | Procottus gurwicii | 46206 |
| Cottus jeittelesii Dybowski, 1874 | Procottus jeittelesii | 26282 |
| Elanura jordani Schmidt, 1903 | Triglops jordani | 7297 |
| Hemilepidotus jordani Bean, 1881 | Hemilepidotus jordani | 6793 |
| Prionistius jordani Jordan & Starks, 1904 | Triglops jordani | 54621 |
| Cottus kaganowskii Berg, 1932 | Cottus cognatus | 54621 |
| Cottus kanawhae Robins, 2005 | Cottus kanawhae | 54473 |
| Cottus kazika Jordan & Starks, 1904 | Cottus kazika | 559 |
| Paracottus kessleri arachlensis Tarchova, 1962 | Leocottus kesslerii | 57778 |
| Paracottus kessleri gussinensis Tarchova, 1962 | Leocottus kesslerii | 57778 |
| Cottus kesslerii Dybowski, 1874 | Leocottus kesslerii | 26334 |
| Cottus kesslerii bauntovi Taliev, 1946 | Leocottus kesslerii | 50838 |
| Cottus klamathensis Gilbert, 1898 | Cottus klamathensis | 5723 |
| Cottus klamathensis polyporus Daniels & Moyle, 1984 | Cottus klamathensis | 54621 |
| Paracottus kneri putorania Koryakov & Sidelov, 1976 | Paracottus knerii | 50600 |
| Cottus knerii Dybowski, 1874 | Paracottus knerii | 26282 |
| Cottus kolymensis Sideleva & Goto, 2012 | Cottus kolymensis | 93142 |
| Cottus koreanus Fujii, Choi & Yabe, 2005 | Cottus koreanus | 93142 |
| Asprocottus korjakovi Sideleva, 2001 | Asprocottus korjakovi | 53210 |
| Asprocottus korjakovi minor Sideleva, 2001 | Asprocottus minor | 53210 |
| Abyssocottus korotneffi Berg, 1906 | Abyssocottus korotneffi | 42042 |
| Cottus koshewnikowi (non Gratzianov, 1907) | Cottus gobio | 55856 |
| Cottus koshewnikowi Gratzianov, 1907 | Cottus koshewnikowi | 55856 |
| Limnocottus kozovi Taliev, 1946 | Cyphocottus megalops | 46206 |
| Uranidea kumlieni Hoy, 1876 | Cottus bairdii | 54621 |
| Cottus kuznetzovi (non Berg, 1903) | Alpinocottus poecilopus | 93142 |
| Cottus kuznetzovi Berg, 1903 | Cottus kuznetzovi | 93142 |
| Scorpaenichthys lateralis Girard, 1854 | Artedius lateralis | 26282 |
| Acanthocottus laticeps Gilbert, 1896 | Megalocottus platycephalus | 26282 |
| Cottus latifrons Gratzianov, 1904 | Myoxocephalus quadricornis | 13696 |
| Stelgidonotus latifrons Gilbert & Thompson, 1905 | Oligocottus rimensis | 43939 |
| Cottus leiopomus Gilbert & Evermann, 1894 | Cottus leiopomus | 5723 |
| Astrocottus leprops Bolin, 1936 | Astrocottus leprops | 76844 |
| Astrocottus leprops (non Bolin, 1936) | Astrocottus matsubarae | 76844 |
| Porocottus leptosomus Muto, Choi & Yabe, 2002 | Porocottus leptosomus | 44254 |
| Cottus lilljeborgii Collett, 1875 | Micrenophrys lilljeborgii | 12965 |
| Icelinus limbaughi Rosenblatt & Smith, 2004 | Icelinus limbaughi | 75898 |
| Ceratocottus lucasi (non Jordan & Gilbert, 1898) | Enophrys diceraus | 11366 |
| Ceratocottus lucasi Jordan & Gilbert, 1898 | Enophrys lucasi | 33021 |
| Prionistius macellus Bean, 1884 | Triglops macellus | 7297 |
| Pterygiocottus macouni Bean & Weed, 1920 | Artedius harringtoni | 4925 |
| Cottus macrops Rutter, 1908 | Cottus klamathensis | 50838 |
| Cottus maculatus Fischer, 1885 | Taurulus bubalis | 9981 |
| Oligocottus maculosus Girard, 1856 | Oligocottus maculosus | 26282 |
| Icelus mandibularis Yabe, 1983 | Icelus mandibularis | 559 |
| Uranidea marginata Bean, 1881 | Cottus marginatus | 12965 |
| Centridermichthys marmoratus Döderlein, 1884 | Pseudoblennius marmoratus | 26282 |
| Cottus marmoratus Valenciennes, 1832 | Myoxocephalus stelleri | 58496 |
| Ocynectes maschalis Jordan & Starks, 1904 | Ocynectes maschalis | 559 |
| Astrocottus matsubarae Katayama, 1942 | Astrocottus matsubarae | 76844 |
| Myoxocephalus matsubarai Watanabe, 1958 | Myoxocephalus matsubarai | 559 |
| Microcottus matuaensis Yabe & Pietsch, 2003 | Microcottus matuaensis | 49856 |
| Ruscarius meanyi Jordan & Starks, 1895 | Ruscarius meanyi | 3814 |
| Myoxocephalus mednius Bean, 1898 | Porocottus mednius | 43939 |
| Andriashevicottus megacephalus Fedorov, 1990 | Andriashevicottus megacephalus | 41742 |
| Antipodocottus megalops DeWitt, 1969 | Antipodocottus megalops | 5755 |
| Cottus megalops Gratzianov, 1902 | Cyphocottus megalops | 26282 |
| Asprocottus megalops eurystomus Taliev, 1955 | Cyphocottus eurystomus | 26282 |
| Cottus meridionalis Girard, 1850 | Cottus bairdii | 37399 |
| Stlengis mesembrinus Fricke & Brunken, 1983 | Antipodocottus mesembrinus | 34698 |
| Cottus metae Freyhof, Kottelat & Nolte, 2005 | Cottus metae | 55856 |
| Triglops metopias Gilbert & Burke, 1912 | Triglops metopias | 7297 |
| Artediellus miacanthus Gilbert & Burke, 1912 | Artediellus miacanthus | 6876 |
| Uranidea microstoma Lockington, 1880 | Cottus aleuticus | 1998 |
| Cottus microstomus (non Heckel, 1837) | Cottus gobio | 55856 |
| Cottus microstomus Heckel, 1837 | Cottus microstomus | 55856 |
| Cottiusculus minor Watanabe, 1958 | Artediellus minor | 40966 |
| Cottus minutus Pallas, 1814 | Porocottus minutus | 33021 |
| Vellitor minutus Iwata, 1983 | Vellitor minutus | 559 |
| Cottus minutus volki Taranetz, 1933 | Alpinocottus volki | 26282 |
| Schmidtia misakia Jordan & Starks, 1904 | Stlengis misakia | 26282 |
| Ocynectes modestus Snyder, 1911 | Ocynectes modestus | 34595 |
| Triglops murrayi Günther, 1888 | Triglops murrayi | 7297 |
| Cottus nasalis Berg, 1933 | Cottus nasalis | 26334 |
| Artediellus neyelovi Muto, Yabe & Amaoka, 1994 | Artediellus neyelovi | 41299 |
| Cottus niger Bean, 1881 | Myoxocephalus niger | 26282 |
| Artediellus nigripinnis Schmidt, 1937 | Artediellichthys nigripinnis | 43939 |
| Cottiusculus nihonkaiensis Kai & Nakabo, 2009 | Cottiusculus nihonkaiensis | 83439 |
| Cottus nikolskii Berg, 1900 | Batrachocottus nikolskii | 26282 |
| Batrachocottus nikolskii multiradiatus Berg, 1907 | Batrachocottus multiradiatus | 26282 |
| Artedius notospilotus Girard, 1856 | Artedius notospilotus | 2850 |
| Cottus nozawae Snyder, 1911 | Cottus nozawae | 559 |
| Ricuzenius nudithorax Bolin, 1936 | Ricuzenius nudithorax | 559 |
| Triglops nybelini Jensen, 1944 | Triglops nybelini | 7297 |
| Phallocottus obtusus Schultz, 1938 | Phallocottus obtusus | 2850 |
| Artediellus ochotensis Gilbert & Burke, 1912 | Artediellus ochotensis | 559 |
| Icelus ochotensis Schmidt, 1927 | Icelus ochotensis | 559 |
| Zesticelus ochotensis Yabe, 1995 | Zesticelus ochotensis | 13470 |
| Cottus octodecemspinosus Mitchill, 1814 | Myoxocephalus octodecemspinosus | 12965 |
| Icelinus oculatus (non Gilbert, 1890) | Icelinus fimbriatus | 11980 |
| Icelinus oculatus Gilbert, 1890 | Icelinus oculatus | 3814 |
| Alcichthys okiensis Mori, 1956 | Alcichthys elongatus | 41299 |
| Triglops ommatistius Gilbert, 1913 | Triglops murrayi | 7297 |
| Triglops ommatistius terraenovae Gilbert, 1913 | Triglops murrayi | 7297 |
| Cottus onychus Eigenmann & Eigenmann, 1892 | Cottus ricei | 1998 |
| Stlengis osensis Jordan & Starks, 1904 | Stlengis osensis | 559 |
| Furcina osimae Jordan & Starks, 1904 | Furcina osimae | 559 |
| Astrocottus oyamai Watanabe, 1958 | Astrocottus oyamai | 559 |
| Artediellus pacificus Gilbert, 1896 | Artediellus pacificus | 26282 |
| Limnocottus pallidus Taliev, 1948 | Limnocottus pallidus | 26334 |
| Melletes papilio Bean, 1880 | Hemilepidotus papilio | 26282 |
| Myoxocephalus parvulus Gilbert & Burke, 1912 | Microcottus sellaris | 49856 |
| Cottopsis parvus Girard, 1854 | Cottus asper | 1998 |
| Cottus paulus Williams, 2000 | Cottus paulus | 36875 |
| Paracottus pelagicus Taliev, 1955 | Leocottus kesslerii | 85815 |
| Pseudoblennius percoides Günther, 1861 | Pseudoblennius percoides | 559 |
| Cottus perifretum Freyhof, Kottelat & Nolte, 2005 | Cottus perifretum | 55856 |
| Icelus perminovi Taranetz, 1936 | Icelus perminovi | 559 |
| Cottus perplexus Gilbert & Evermann, 1894 | Cottus perplexus | 5723 |
| Cottus petiti Băcescu & Băcescu-Meşter, 1964 | Cottus petiti | 13696 |
| Cottus philonips Eigenmann & Eigenmann, 1892 | Cottus cognatus | 1998 |
| Icelinus pietschi Yabe, Soma & Amaoka, 2001 | Icelinus pietschi | 45337 |
| Ricuzenius pinetorum Jordan & Starks, 1904 | Ricuzenius pinetorum | 559 |
| Triglops pingelii Reinhardt, 1837 | Triglops pingelii | 12965 |
| Triglops pingelii islandicus Jensen, 1944 | Triglops murrayi | 7297 |
| Triglops pingelii pacificus Schmidt, 1930 | Triglops pingelii | 10937 |
| Triglops pingelii pietschmanni Jensen, 1944 | Triglops murrayi | 7297 |
| Triglops pingelii typicus Le Danois, 1914 | Triglops pingelii | 7297 |
| Triglops pingelii var. subborealis Le Danois, 1914 | Triglops murrayi | 7297 |
| Cottus pistilliger Pallas, 1814 | Gymnocanthus pistilliger | 26282 |
| Cottus pitensis Bailey & Bond, 1963 | Cottus pitensis | 5723 |
| Cottus platycephalus Pallas, 1814 | Megalocottus platycephalus | 12965 |
| Triglops pleurostictus Cope, 1865 | Triglops pingelii | 7297 |
| Archistes plumarius Jordan & Gilbert, 1898 | Archistes plumarius | 43939 |
| Cottus poecilopus Heckel, 1837 | Alpinocottus poecilopus | 55856 |
| Cottus poecilopus altaicus (non Kaschenko, 1899) | Alpinocottus poecilopus | 57778 |
| Cottus poecilopus altaicus Kaschenko, 1899 | Cottus altaicus | 57778 |
| Cottus poecilopus macrostomus Jeitteles, 1862 | Alpinocottus poecilopus | 13696 |
| Cottus poecilopus microstomus Jeitteles, 1862 | Alpinocottus poecilopus | 13696 |
| Uranidea pollicaris Jordan & Gilbert, 1882 | Cottus ricei | 1998 |
| Cottus pollux Günther, 1873 | Cottus pollux | 559 |
| Cottus polyacanthocephalus Pallas, 1814 | Myoxocephalus polyacanthocephalus | 26282 |
| Cottiusculus primoricus Prokofiev, 2020 | Cottiusculus primoricus | 123154 |
| Cottus princeps Gilbert, 1898 | Cottus princeps | 5723 |
| Acanthocottus profundorum Gilbert, 1896 | Zesticelus profundorum | 26282 |
| Cottus protrusus Schultz & Spoor, 1933 | Cottus aleuticus | 10280 |
| Artedius pugetensis Steindachner, 1876 | Chitonotus pugetensis | 26282 |
| Asprocottus pulcher Taliev, 1955 | Asprocottus pulcher | 26334 |
| Abyssocottus pumilus Bogdanov, 2014 | Abyssocottus pumilus | 130169 |
| Potamocottus punctulatus Gill, 1861 | Cottus bairdii | 54621 |
| Cottus pygmaeus Williams, 1968 | Cottus paulus | 5723 |
| Porocottus quadratus Bean, 1898 | Microcottus sellaris | 49856 |
| Cottus quadricornis Linnaeus, 1758 | Myoxocephalus quadricornis | 86838 |
| Cottus quadricornis asundensis Lönnberg, 1932 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis borkensis Lönnberg, 1939 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis frykenensis Lönnberg, 1932 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis kallavesensis Lönnberg, 1933 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis lonnbergi Lönnberg, 1919 | Myoxocephalus quadricornis | 13696 |
| Myoxocephalus quadricornis lonnbergi Berg, 1916 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis oernensis Lönnberg, 1932 | Myoxocephalus quadricornis | 13696 |
| Myoxocephalus quadricornis onegensis Berg & Popov, 1932 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis pygmaeus Lönnberg, 1933 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis relicta Lilljeborg, 1891 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis vaenernensis Lönnberg, 1932 | Myoxocephalus quadricornis | 13696 |
| Cottus quadricornis vermelnensis Nybelin, 1940 | Myoxocephalus quadricornis | 13696 |
| Porocottus quadrifilis Gill, 1859 | Porocottus quadrifilis | 6876 |
| Artedius quadriseriatus Lockington, 1880 | Icelinus quadriseriatus | 12965 |
| Uranidea quiescens DeKay, 1842 | Cottus cognatus | 1998 |
| Myoxocephalus raninus Jordan & Starks, 1904 | Myoxocephalus stelleri | 43939 |
| Icelus rastrinoides Taranetz, 1936 | Icelus rastrinoides | 27683 |
| Blennicottus recalvus Greeley, 1899 | Clinocottus recalvus | 12965 |
| Astrocottus regulus Tsuruoka, Maruyama & Yabe, 2008 | Astrocottus regulus | 76844 |
| Cottus reinii Hilgendorf, 1879 | Cottus reinii | 559 |
| Cottus rhenanus Freyhof, Kottelat & Nolte, 2005 | Cottus rhenanus | 55856 |
| Ascelichthys rhodorus Jordan & Gilbert, 1880 | Ascelichthys rhodorus | 26282 |
| Uranidea rhothea Smith, 1882 | Cottus rhotheus | 1998 |
| Cottopsis ricei Nelson, 1876 | Cottus ricei | 1998 |
| Cottus richardsoni Agassiz, 1850 | Cottus bairdii | 1998 |
| Trachidermus richardsonii Heckel, 1837 | Cottus asper | 1998 |
| Rusciculus rimensis Greeley, 1899 | Oligocottus rimensis | 26282 |
| Cottus rondeleti Freyhof, Kottelat & Nolte, 2005 | Cottus rondeleti | 55856 |
| Eximia rubellio Greeley, 1899 | Oligocottus rubellio | 12965 |
| Cottus sabaudicus Sideleva, 2009 | Cottus sabaudicus | 81212 |
| Daruma sagamia Jordan & Starks, 1904 | Daruma sagamia | 559 |
| Artediellus scaber Knipowitsch, 1907 | Artediellus scaber | 4698 |
| Artediellus scaber beringianus Schmidt, 1927 | Artediellus scaber | 10937 |
| Cottus scaturigo Freyhof, Kottelat & Nolte, 2005 | Cottus gobio | 129293 |
| Triglops scepticus Gilbert, 1896 | Triglops scepticus | 7297 |
| Cottus schitsuumsh Lemoine, Young, Mckelvey, Eby, Pilgrim & Schwartz, 2014 | Cottus schitsuumsh | 94998 |
| Artediellus schmidti Soldatov, 1915 | Artediellus schmidti | 26282 |
| Cottiusculus schmidti (non Jordan & Starks, 1904) | Cottiusculus nihonkaiensis | 83439 |
| Cottiusculus schmidti Jordan & Starks, 1904 | Cottiusculus schmidti | 559 |
| Cottus scorpioides Fabricius, 1780 | Myoxocephalus scorpioides | 80565 |
| Cottus scorpius Linnaeus, 1758 | Myoxocephalus scorpius | 43939 |
| Icelus scutiger Bean, 1890 | Rastrinus scutiger | 6876 |
| Icelus sekii Tsuruoka, Munehara & Yabe, 2006 | Icelus sekii | 58328 |
| Acanthocottus sellaris Gilbert, 1896 | Microcottus sellaris | 26282 |
| Porocottus sellaris ochotensis Schmidt, 1929 | Microcottus sellaris | 49856 |
| Cottopsis semiscaber Cope, 1872 | Cottus bairdii | 93641 |
| Cottus sibiricus Warpachowski, 1889 | Cottus sibiricus | 26334 |
| Cottus sibiricus altaicus Li & Ho, 1966 | Cottus dzungaricus | 57778 |
| Cottus sinensis Sauvage, 1873 | Myoxocephalus sinensis | 46206 |
| Lepidobero sinensis Qin & Jin, 1992 | Lepidobero sinensis | 31517 |
| Sigmistes smithi Schultz, 1938 | Sigmistes smithi | 45337 |
| Oligocottus snyderi Greeley, 1898 | Oligocottus snyderi | 26282 |
| Icelus spatula Gilbert & Burke, 1912 | Icelus spatula | 7251 |
| Cottus specus Adams & Burr, 2013 | Cottus specus | 92978 |
| Icelus spiniger Gilbert, 1896 | Icelus spiniger | 6793 |
| Hemilepidotus spinosus Ayres, 1854 | Hemilepidotus spinosus | 12965 |
| Cottus spinulosus Kessler, 1872 | Cottus spinulosus | 2058 |
| Stelgistrum stejnegeri Jordan & Gilbert, 1898 | Stelgistrum stejnegeri | 559 |
| Myoxocephalus stelleri Tilesius, 1811 | Myoxocephalus stelleri | 43939 |
| Cottus szanaga Dybowski, 1869 | Cottus szanaga | 53210 |
| Cottus taeniopterus (non Kner, 1868) | Megalocottus platycephalus | 11366 |
| Cottus taeniopterus Kner, 1868 | Megalocottus taeniopterus | 26282 |
| Cottus taeniopterus (non Kner, 1868) | Myoxocephalus jaok | 11366 |
| Batrachocottus talievi Sideleva, 1999 | Batrachocottus talievi | 53210 |
| Cottus tallapoosae Neely, Williams & Mayden, 2007 | Cottus tallapoosae | 72414 |
| Radulinopsis taranetzi Yabe & Maruyama, 2001 | Radulinopsis taranetzi | 45347 |
| Enophrys taurina Gilbert, 1914 | Enophrys taurina | 2850 |
| Asemichthys taylori Gilbert, 1912 | Asemichthys taylori | 43939 |
| Cottus tentaculatus Kner, 1868 | Porocottus tentaculatus | 559 |
| Icelinus tenuis Gilbert, 1890 | Icelinus tenuis | 2850 |
| Uranidea tenuis Evermann & Meek, 1898 | Cottus tenuis | 12965 |
| Neocottus thermalis Sideleva, 2002 | Neocottus thermalis | 53210 |
| Triglopsis thompsonii Girard, 1851 | Myoxocephalus thompsonii | 54621 |
| Pseudoblennius totomius Jordan & Starks, 1904 | Pseudoblennius totomius | 41299 |
| Ricuzenius toyamensis Matsubara & Iwai, 1951 | Icelus toyamensis | 40966 |
| Cottus trachurus Pallas, 1814 | Hemilepidotus hemilepidotus | 93382 |
| Cottus transsilvaniae Freyhof, Kottelat & Nolte, 2005 | Cottus transsilvaniae | 55856 |
| Orthonopias triacis Starks & Mann, 1911 | Orthonopias triacis | 2850 |
| Atopocottus tribranchius Bolin, 1936 | Atopocottus tribranchius | 559 |
| Cottus tricuspis Reinhardt, 1830 | Gymnocanthus tricuspis | 12965 |
| Gymnacanthus tricuspis orientalis Schmidt, 1927 | Gymnocanthus tricuspis | 114903 |
| Cottus trigonocephalus Gratzianov, 1902 | Leocottus kesslerii | 57778 |
| Myoxocephalus tuberculatus Soldatov & Pavlenko, 1922 | Myoxocephalus tuberculatus | 46206 |
| Triglops uchidai Watanabe, 1958 | Triglops scepticus | 7297 |
| Icelus uncinalis Gilbert & Burke, 1912 | Icelus uncinalis | 6876 |
| Icelus uncinalis stenosomus Andriashev, 1937 | Icelus stenosomus | 27737 |
| Cottus uncinatus Reinhardt, 1834 | Artediellus uncinatus | 58462 |
| Gymnocanthus vandesandei Poll, 1949 | Gymnocanthus vandesandei | 46206 |
| Cottus ventralis Cuvier, 1829 | Gymnocanthus pistilliger | 121848 |
| Cottus verrucosus Bean, 1881 | Myoxocephalus scorpius | 43939 |
| Myoxocephalus verrucosus ochotensis Schmidt, 1929 | Myoxocephalus ochotensis | 46206 |
| Icelus vicinalis Gilbert, 1896 | Icelus euryops | 11366 |
| Radulinus vinculus Bolin, 1950 | Radulinus vinculus | 2850 |
| Abyssocottus werestschagini Taliev, 1935 | Neocottus werestschagini | 2058 |
| Stlegicottus xenogrammus Bolin, 1936 | Rastrinus scutiger | 86856 |
| Triglops xenostethus Gilbert, 1896 | Triglops xenostethus | 7297 |
| Myoxocephalus yesoensis Snyder, 1911 | Myoxocephalus yesoensis | 46206 |
| Bero zanclus Snyder, 1911 | Alcichthys elongatus | 43239 |
| Argyrocottus zanderi Herzenstein, 1892 | Argyrocottus zanderi | 559 |
| Hemilepidotus zapus Gilbert & Burke, 1912 | Hemilepidotus zapus | 2850 |
| Pseudoblennius zonostigma Jordan & Starks, 1904 | Pseudoblennius zonostigma | 559 |