| Nominal Species (n = 527) | Present allocation (n = 460) | Ref. |
|---|---|---|
| Austrolebias accorsii Nielsen & Pillet, 2015 | Austrolebias accorsii | 129129 |
| Neofundulus acutirostratus Costa, 1992 | Neofundulus acutirostratus | 36579 |
| Cynolebias adloffi Ahl, 1922 | Austrolebias adloffi | 27139 |
| Simpsonichthys adornatus Costa, 2000 | Hypsolebias adornatus | 44211 |
| Cynolebias affinis Amato, 1986 | Austrolebias affinis | 36579 |
| Rivulus agilae Hoedeman, 1954 | Laimosemion agilae | 36579 |
| Melanorivulus aithogrammus Nielsen & Britzke, 2019 | Melanorivulus aithogrammus | 128908 |
| Cynolebias akroa Nielsen, Martins, Araujo, Lira & Faour, 2018 | Cynolebias akroa | 127992 |
| Rivulus albae Valdesalici, García Gil & Bressane Nielsen, 2011 | Melanorivulus schuncki | 92137 |
| Cynolebias albipunctatus Costa & Brasil, 1991 | Cynolebias porosus | 97357 |
| Cynolebias alexandri Castello & López, 1974 | Austrolebias alexandri | 27139 |
| Plesiolebias altamira Costa & Nielsen, 2007 | Plesiolebias altamira | 57947 |
| Cynolebias alternatus Costa & Brasil, 1994 | Simpsonichthys alternatus | 49550 |
| Rivulus altivelis Huber, 1992 | Laimosemion altivelis | 36579 |
| Cynolebias altus Costa, 2001 | Cynolebias altus | 40938 |
| Melanorivulus amambaiensis Volcan, Severo-Neto & Lanés, 2018 | Melanorivulus amambaiensis | 119399 |
| Rivulus amanan Costa & Lazzarotto, 2008 | Anablepsoides amanan | 78702 |
| Rivulus amanapira Costa, 2004 | Laimosemion amanapira | 52792 |
| Rivulus amphoreus Huber, 1979 | Anablepsoides amphoreus | 36579 |
| Cynolebias antenori Tulipano, 1973 | Hypsolebias antenori | 36579 |
| Cynolebias antenori Myers, 1952 | Hypsolebias antenori | 36579 |
| Austrolebias apaii Costa, Laurino, Recuero & Salvia, 2006 | Austrolebias bellottii | 116996 |
| Rivulus apiamici (non Costa, 1989) | Melanorivulus pictus | 36579 |
| Rivulus apiamici Costa, 1989 | Melanorivulus apiamici | 36579 |
| Trigonectes aplocheiloides Huber, 1995 | Trigonectes aplocheiloides | 36579 |
| Moema apurinan Costa, 2004 | Moema apurinan | 52556 |
| Austrolebias arachan Loureiro, Azpelicueta & García, 2004 | Austrolebias arachan | 55775 |
| Austrolebias araucarianus Costa, 2014 | Austrolebias araucarianus | 97355 |
| Cynolebias aruana Lazara, 1991 | Plesiolebias aruana | 36579 |
| Papiliolebias ashleyae Nielsen & Brousseau, 2014 | Papiliolebias ashleyae | 94790 |
| Melanorivulus atlanticus Costa, Bragança & Ottoni, 2015 | Melanorivulus atlanticus | 101434 |
| Rivulus atratus Garman, 1895 | Anablepsoides atratus | 36579 |
| Cynolebias attenuatus Costa, 2001 | Cynolebias attenuatus | 40938 |
| Simpsonichthys auratus Costa & Nielsen, 2000 | Hypsolebias auratus | 36579 |
| Cynolebias aureoguttatus da Cruz, 1974 | Leptolebias aureoguttatus | 36579 |
| Cynolebias aureoguttatus Myers, 1952 | Leptolebias aureoguttatus | 36579 |
| Neofundulus aureomaculatus Costa, 2015 | Neofundulus aureomaculatus | 101435 |
| Prorivulus auriferus Costa, Lima & Suzart, 2004 | Prorivulus auriferus | 54792 |
| Rivulus azurescens Vermeulen, 2013 | Rivulus azurescens | 95022 |
| Austrolebias bagual Volcan, Lanés & Gonçalves, 2014 | Austrolebias bagual | 118216 |
| Rivulus bahianus Huber, 1990 | Anablepsoides bahianus | 36579 |
| Haplochilus balzanii Perugia, 1891 | Trigonectes balzanii | 36579 |
| Cynolebias bellottii Steindachner, 1881 | Austrolebias bellottii | 36579 |
| Stenolebias bellus Costa, 1995 | Stenolebias bellus | 36579 |
| Rivulus beniensis beniensis Myers, 1927 | Anablepsoides beniensis | 27139 |
| Rivulus beniensis lacustris Myers, 1927 | Anablepsoides beniensis | 36579 |
| Rivulus berovidesi Silva, 2015 | Rivulus berovidesi | 101368 |
| Moema beucheyi Valdesalici, Nielsen & Pillet, 2015 | Moema beucheyi | 110333 |
| Anablepsoides bibosi Valdesalici & Gil, 2019 | Anablepsoides bibosi | 130459 |
| Rivulus birkhahni Berkenkamp & Etzel, 1992 | Cynodonichthys birkhahni | 36579 |
| Plesiolebias bitteri Costa, 1989 | Papiliolebias bitteri | 36579 |
| Rivulus boehlkei Huber & Fels, 1985 | Cynodonichthys boehlkei | 36579 |
| Simpsonichthys boitonei Carvalho, 1959 | Simpsonichthys boitonei | 36579 |
| Cynolebias bokermanni Carvalho & da Cruz, 1987 | Simpsonichthys bokermanni | 27139 |
| Pterolebias bokermanni Travassos, 1955 | Pterolebias longipinnis | 57631 |
| Rivulus bolivianus Seegers, 1988 | Anablepsoides beniensis | 36579 |
| Rivulus bondi (non Schultz, 1949) | Anablepsoides hartii | 89845 |
| Rivulus bondi Schultz, 1949 | Anablepsoides bondi | 36579 |
| Rivulus bororo Costa, 2008 | Melanorivulus bororo | 76975 |
| Aphyolebias boticarioi Costa, 2004 | Aphyolebias boticarioi | 52556 |
| Austrolebias botocudo Lanés, Volcan & Maltchik, 2021 | Austrolebias botocudo | 123906 |
| Fundulus brasiliensis Valenciennes, 1821 | Kryptolebias brasiliensis | 36579 |
| Rivulus breviceps Eigenmann, 1909 | Laimosemion breviceps | 36579 |
| Pituna brevirostrata Costa, 2007 | Pituna brevirostrata | 57947 |
| Rivulus brevis Regan, 1912 | Rachovia brevis | 36579 |
| Spectrolebias brousseaui Nielsen, 2013 | Spectrolebias brousseaui | 93219 |
| Campellolebias brucei Vaz-Ferreira & Sierra de Soriano, 1974 | Campellolebias brucei | 36579 |
| Rivulus brunneus Meek & Hildebrand, 1913 | Cynodonichthys brunneus | 36579 |
| Simpsonichthys brunoi Costa, 2003 | Hypsolebias brunoi | 49550 |
| Hypsolebias caeruleus Costa, 2013 | Hypsolebias caeruleus | 94796 |
| Rivulus cajariensis Costa & De Luca, 2011 | Anablepsoides cajariensis | 86530 |
| Austrolebias camaquensis Volcan, Gonçalves & Lanés, 2017 | Austrolebias camaquensis | 128880 |
| Rivulus campelloi Costa, 1990 | Kryptolebias campelloi | 36579 |
| Plesiolebias canabravensis Costa & Nielsen, 2007 | Plesiolebias canabravensis | 57947 |
| Simpsonichthys carlettoi Costa & Nielsen, 2004 | Hypsolebias carlettoi | 54621 |
| Rivulus carolinae Vermeulen & Mejia-Vargas, 2020 | Rivulus carolinae | 130065 |
| Cynolebias carvalhoi Myers, 1947 | Austrolebias carvalhoi | 36579 |
| Nematolebias catimbau Costa, Amorim & Aranha, 2014 | Nematolebias catimbau | 95536 |
| Rivulus caudomarginatus Seegers, 1984 | Kryptolebias caudomarginatus | 52570 |
| Rivulus caurae Radda, 2004 | Anablepsoides caurae | 55923 |
| Rivulus cearensis Costa & Vono, 2009 | Anablepsoides cearensis | 81224 |
| Cynolebias chacoensis Amato, 1986 | Spectrolebias chacoensis | 27139 |
| Anablepsoides chapare Valdesalici & Gil, 2017 | Anablepsoides chapare | 130460 |
| Austrolebias charrua Costa & Cheffe, 2001 | Austrolebias charrua | 44045 |
| Austrolebias cheffei Volcan, Barbosa, Robe & Lanés, 2021 | Austrolebias cheffei | 129237 |
| Cynolebias cheradophilus Vaz-Ferreira, Sierra de Soriano & Scaglia de Paulete, 1965 | Austrolebias cheradophilus | 36579 |
| Simpsonichthys cholopteryx Costa, Moreira & Lima, 2003 | Simpsonichthys cholopteryx | 50838 |
| Rivulus christinae Huber, 1992 | Anablepsoides christinae | 36579 |
| Campellolebias chrysolineatus Costa, Lacerda & Brasil, 1989 | Campellolebias chrysolineatus | 36579 |
| Rivulus chucunaque Breder, 1925 | Cynodonichthys chucunaque | 36579 |
| Rivulus chucunaque (non Breder, 1925) | Cynodonichthys sucubti | 89845 |
| Rivulus chucunaque sucubti Breder, 1925 | Cynodonichthys sucubti | 36579 |
| Rivulus chucunaque sucubti (non Breder, 1925) | Cynodonichthys chucunaque | 89845 |
| Cynolebias cinereus Amato, 1986 | Austrolebias cinereus | 46206 |
| Cynolebias citrinipinnis Costa, Lacerda & Tanizaki, 1988 | Leptolebias citrinipinnis | 36579 |
| Rivulus cladophorus Huber, 1991 | Laimosemion cladophorus | 36579 |
| Aphyolebias claudiae Costa, 2003 | Aphyolebias claudiae | 54621 |
| Hypsolebias coamazonicus Costa, Amorim & Bragança, 2014 | Hypsolebias coamazonicus | 94133 |
| Rivulus compactus Myers, 1927 | Pituna compacta | 36579 |
| Rivulus compressus Henn, 1916 | Anablepsoides micropus | 42871 |
| Cynolebias constanciae Myers, 1942 | Simpsonichthys constanciae | 36579 |
| Rivulus corpulentus Thomerson & Taphorn, 1993 | Laimosemion corpulentus | 36579 |
| Cynolebias costai Lazara, 1991 | Spectrolebias costai | 36579 |
| Xenurolebias cricarensis Costa, 2014 | Xenurolebias cricarensis | 96072 |
| Rivulus crixas Costa, 2007 | Melanorivulus crixas | 59346 |
| Cynolebias cruzi Costa, 1988 | Notholebias cruzi | 36579 |
| Rivulus cryptocallus Seegers, 1980 | Anablepsoides cryptocallus | 36579 |
| Cynolebias cyaneus (non Amato, 1987) | Austrolebias affinis | 36579 |
| Cynolebias cyaneus Amato, 1987 | Austrolebias cyaneus | 36579 |
| Rivulus cyanopterus Costa, 2005 | Melanorivulus cyanopterus | 54355 |
| Rivulus cylindraceus Poey, 1860 | Rivulus cylindraceus | 36579 |
| Plesiolebias damascenoi Costa, 1991 | Stenolebias damascenoi | 36579 |
| Rivulus dapazi Costa, 2005 | Melanorivulus dapazi | 54355 |
| Rivulus decoratus Costa, 1989 | Melanorivulus decoratus | 36579 |
| Rivulus deltaphilus Seegers, 1983 | Anablepsoides deltaphilus | 36579 |
| Simpsonichthys delucai Costa, 2003 | Simpsonichthys delucai | 49550 |
| Rivulus depressus Costa, 1991 | Atlantirivulus depressus | 36579 |
| Rivulus derhami Fels & Huber, 1985 | Anablepsoides derhami | 36579 |
| Rivulus dibaphus Myers, 1927 | Laimosemion dibaphus | 36579 |
| Austrofundulus dolichopterus Weitzman & Wourms, 1967 | Terranatos dolichopterus | 36579 |
| Rivulus dorni Myers, 1924 | Kryptolebias brasiliensis | 36579 |
| Campellolebias dorsimaculatus Costa, Lacerda & Brasil, 1989 | Campellolebias dorsimaculatus | 36579 |
| Rivulus duckensis Hrbek, de Deus & Farias, 2004 | Laimosemion kirovskyi | 81833 |
| Cynolebias duraznensis García, Scvortzoff & Hernández, 1995 | Austrolebias duraznensis | 57613 |
| Cynolebias duraznensis (non García, Scvortzoff & Hernández, 1995) | Austrolebias affinis | 36579 |
| Cynolebias duraznensis Reichert, 1992 | Austrolebias affinis | 50838 |
| Rivulus egens Costa, 2005 | Melanorivulus egens | 54355 |
| Cynolebias elegans Costa, 2017 | Cynolebias elegans | 118117 |
| Pterolebias elegans Ladiges, 1958 | Nematolebias whitei | 36579 |
| Rivulus elegans Steindachner, 1880 | Cynodonichthys elegans | 36579 |
| Rivulus elegans santensis Köhler, 1906 | Atlantirivulus santensis | 92135 |
| Cynolebias elongatus Steindachner, 1881 | Austrolebias elongatus | 36579 |
| Rivulus elongatus Fels & de Rham, 1981 | Anablepsoides elongatus | 36579 |
| Austrolebias ephemerus Volcan & Severo-Neto, 2019 | Austrolebias ephemerus | 119764 |
| Rivulus erberi Berkenkamp, 1989 | Anablepsoides erberi | 36579 |
| Hypsolebias faouri Britzke, Nielsen & Oliveira, 2016 | Hypsolebias faouri | 108434 |
| Simpsonichthys fasciatus Costa & Brasil, 2006 | Simpsonichthys fasciatus | 57612 |
| Rivulus faucireticulatus Costa, 2008 | Melanorivulus faucireticulatus | 75134 |
| Plesiolebias filamentosus Costa & Brasil, 2007 | Plesiolebias filamentosus | 57947 |
| Simpsonichthys filamentosus Costa, Barrera & Sarmiento, 1997 | Spectrolebias filamentosus | 93219 |
| Rivulus flabellicauda Regan, 1907 | Cynodonichthys isthmensis | 36579 |
| Simpsonichthys flagellatus Costa, 2003 | Hypsolebias flagellatus | 49550 |
| Rivulus flammaecauda Vermeulen & Mejia-Vargas, 2020 | Rivulus flammaecauda | 130065 |
| Cynolebias flammeus Costa, 1989 | Hypsolebias flammeus | 49550 |
| Cynolebias flavicaudatus Costa & Brasil, 1990 | Hypsolebias flavicaudatus | 26744 |
| Cynopoecilus fluminensis Faria & Muller, 1937 | Leptolebias opalescens | 36579 |
| Cynopoecilus foerschi Knaack, 1970 | Notholebias minimus | 27139 |
| Maratecoara formosa Costa & Brasil, 1995 | Maratecoara formosa | 36579 |
| Rivulus formosensis Costa, 2008 | Rivulus formosensis | 75995 |
| Cynolebias fractifasciatus Costa, 1988 | Notholebias fractifasciatus | 36579 |
| Plesiolebias fragilis Costa, 2007 | Plesiolebias fragilis | 57947 |
| Papiliolebias francescae Valdesalici & Brousseau, 2014 | Papiliolebias francescae | 111235 |
| Anablepsoides fransvermeuleni Valdesalici, 2015 | Anablepsoides fransvermeuleni | 119428 |
| Rachovia fransvermeuleni Berkenkamp, 2020 | Rachovia fransvermeuleni | 122621 |
| Rivulus frenatus Eigenmann, 1912 | Laimosemion frenatus | 36579 |
| Rivulus frommi Berkenkamp & Etzel, 1993 | Cynodonichthys frommi | 36579 |
| Cynopoecilus fulgens Costa, 2002 | Cynopoecilus fulgens | 42931 |
| Cynolebias fulminantis Costa & Brasil, 1993 | Hypsolebias fulminantis | 36579 |
| Cynolebias fulminantis (non Costa & Brasil, 1993) | Hypsolebias hellneri | 36579 |
| Moema funkneri Valdesalici, 2019 | Moema funkneri | 130493 |
| Rivulus fuscolineatus Bussing, 1980 | Cynodonichthys fuscolineatus | 36579 |
| Anablepsoides gamae Costa, Bragança & Amorim, 2013 | Anablepsoides gamae | 94717 |
| Rivulus garciai de la Cruz & Dubitsky, 1976 | Kryptolebias marmoratus | 80809 |
| Hypsolebias gardneri Costa, Amorim & Mattos, 2018 | Hypsolebias gardneri | 128003 |
| Rivulus gaucheri Keith, Nandrin & Le Bail, 2006 | Anablepsoides gaucheri | 78216 |
| Rivulus geayi Vaillant, 1899 | Laimosemion geayi | 36579 |
| Maratecoara gesmonei Nielsen, Martins & Britzke, 2014 | Maratecoara gesmonei | 95615 |
| Simpsonichthys ghisolfii Costa, Cyrino & Nielsen, 1996 | Hypsolebias ghisolfii | 36579 |
| Rivulus giarettai Costa, 2008 | Melanorivulus giarettai | 75625 |
| Simpsonichthys gibberatus Costa & Brasil, 2006 | Simpsonichthys gibberatus | 57612 |
| Cynolebias gibberosus Berg, 1897 | Austrolebias bellottii | 36579 |
| Cynolebias gibbus Costa, 2001 | Cynolebias gibbus | 40938 |
| Hypsolebias gilbertobrasili Costa, 2012 | Hypsolebias gilbertobrasili | 89836 |
| Cynolebias gilbertoi Costa, 1998 | Cynolebias gilbertoi | 36579 |
| Cynolebias glaucopterus Costa & Lacerda, 1989 | Plesiolebias glaucopterus | 36579 |
| Rivulus glaucus Bussing, 1980 | Cynodonichthys glaucus | 36579 |
| Rivulus godmani Regan, 1907 | Cynodonichthys godmani | 36579 |
| Rivulus godmani (non Regan, 1907) | Cynodonichthys tenuis | 89845 |
| Cynolebias gorutuba Costa, 2017 | Cynolebias gorutuba | 118117 |
| Kryptolebias gracilis Costa, 2007 | Kryptolebias gracilis | 72398 |
| Spectrolebias gracilis Costa & Amorim, 2018 | Spectrolebias gracilis | 119392 |
| Rivulus gransabanae Lasso, Taphorn & Thomerson, 1992 | Laimosemion gransabanae | 26072 |
| Cynolebias griseus Costa, Lacerda & Brasil, 1990 | Cynolebias griseus | 36579 |
| Austrofundulus guajira Hrbek, Taphorn & Thomerson, 2005 | Austrofundulus guajira | 54496 |
| Atlantirivulus guanabarensis Costa, 2014 | Atlantirivulus guanabarensis | 102354 |
| Hypsolebias guanambi Costa & Amorim, 2011 | Hypsolebias guanambi | 87364 |
| Neofundulus guaporensis Costa, 1988 | Neofundulus guaporensis | 36579 |
| Argolebias guarani Alonso, Calviño, Terán, Serra, Montes, García, Barneche, Almirón et al., 2023 | Austrolebias guarani | 129129 |
| Cynolebias gymnoventris Amato, 1986 | Austrolebias gymnoventris | 27139 |
| Hypsolebias hamadryades Costa, Amorim & Mattos, 2018 | Hypsolebias hamadryades | 128003 |
| Rivulus haraldsiolii Berkenkamp, 1984 | Atlantirivulus haraldsiolii | 36579 |
| Simpsonichthys harmonicus Costa, 2010 | Hypsolebias harmonicus | 84055 |
| Haplochilus hartii Boulenger, 1890 | Anablepsoides hartii | 36579 |
| Papiliolebias hatinne Azpelicueta, Butí & García, 2009 | Papiliolebias hatinne | 83455 |
| Cynolebias hellneri Berkenkamp, 1993 | Hypsolebias hellneri | 27139 |
| Moema hellneri Costa, 2003 | Moema hellneri | 50838 |
| Cynolebias heloplites Huber, 1981 | Hypsolebias antenori | 27139 |
| Rivulus hendrichsi Álvarez & Carranza, 1952 | Cynodonichthys hendrichsi | 36579 |
| Anablepsoides henschelae Costa, Bragança & Amorim, 2013 | Anablepsoides henschelae | 94717 |
| Kryptolebias hermaphroditus Costa, 2011 | Kryptolebias hermaphroditus | 87200 |
| Moema heterostigma Costa, 2003 | Moema heterostigma | 52822 |
| Rivulus heyei Nichols, 1914 | Kryptolebias marmoratus | 36579 |
| Rivulus hildebrandi Myers, 1927 | Cynodonichthys hildebrandi | 36579 |
| Pterolebias hoignei Thomerson, 1974 | Pterolebias hoignei | 27139 |
| Cynolebias holmbergi Berg, 1897 | Austrolebias elongatus | 36579 |
| Rivulus holmiae Eigenmann, 1909 | Anablepsoides holmiae | 36579 |
| Rachovia hummelincki de Beaufort, 1940 | Rachovia hummelincki | 36579 |
| Cynolebias ibicuiensis Costa, 1999 | Austrolebias ibicuiensis | 36604 |
| Rivulus igneus Huber, 1991 | Anablepsoides igneus | 36579 |
| Simpsonichthys igneus Costa, 2000 | Hypsolebias igneus | 44211 |
| Simpsonichthys ilheusensis Costa & Lima, 2010 | Ophthalmolebias ilheusensis | 86878 |
| Rivulus illuminatus Costa, 2007 | Melanorivulus illuminatus | 78126 |
| Rivulus immaculatus Thomerson, Nico & Taphorn, 1991 | Anablepsoides immaculatus | 36579 |
| Melanorivulus imperatrizensis Nielsen & Pinto, 2015 | Melanorivulus imperatrizensis | 119335 |
| Simpsonichthys inaequipinnatus Costa & Brasil, 2008 | Spectrolebias inaequipinnatus | 79814 |
| Rivulus insulaepinorum de la Cruz & Dubitsky, 1976 | Rivulus insulaepinorum | 36579 |
| Campellolebias intermedius Costa & De Luca, 2006 | Campellolebias intermedius | 57633 |
| Rivulus intermittens Fels & de Rham, 1981 | Anablepsoides intermittens | 36579 |
| Melanorivulus interruptus Volcan, Severo-Neto & Lanés, 2018 | Melanorivulus interruptus | 119399 |
| Cynopoecilus intimus Costa, 2002 | Cynopoecilus intimus | 42931 |
| Rivulus iridescens Fels & de Rham, 1981 | Anablepsoides iridescens | 36579 |
| Cynolebias irregularis Ahl, 1938 | Austrolebias bellottii | 36579 |
| Rivulus isthmensis Garman, 1895 | Cynodonichthys isthmensis | 36579 |
| Rivulus isthmensis rubripunctatus Bussing, 1980 | Cynodonichthys rubripunctatus | 36579 |
| Leptolebias itanhaensis Costa, 2008 | Leptolebias itanhaensis | 75888 |
| Cynolebias itapicuruensis Costa, 2001 | Cynolebias itapicuruensis | 40938 |
| Melanorivulus ivinhemensis Volcan, Severo-Neto & Lanés, 2018 | Melanorivulus ivinhemensis | 119399 |
| Cynolebias izecksohni (non Cruz, 1983) | Xenurolebias myersi | 36579 |
| Cynolebias izecksohni Da Cruz, 1983 | Xenurolebias izecksohni | 96072 |
| Austrolebias jaegari Costa & Cheffe, 2002 | Austrolebias jaegari | 57613 |
| Rivulus jalapensis Costa, 2010 | Melanorivulus jalapensis | 85564 |
| Simpsonichthys janaubensis Costa, 2006 | Hypsolebias janaubensis | 89836 |
| Rivulus janeiroensis Costa, 1991 | Atlantirivulus janeiroensis | 36579 |
| Anablepsoides jari Costa, Bragança & Amorim, 2013 | Anablepsoides jari | 94717 |
| Laimosemion jauaperi Costa & Bragança, 2013 | Laimosemion jauaperi | 130532 |
| Rivulus javahe Costa, 2007 | Melanorivulus javahe | 59346 |
| Moema juanderibaensis Drawert, 2022 | Moema juanderibaensis | 128719 |
| Austrolebias juanlangi Costa, Cheffe, Salvia & Litz, 2006 | Austrolebias juanlangi | 57613 |
| Rivulus jucundus Huber, 1992 | Anablepsoides jucundus | 36579 |
| Rivulus jurubatibensis Costa, 2008 | Atlantirivulus jurubatibensis | 78703 |
| Rivulus karaja Costa, 2007 | Melanorivulus karaja | 59346 |
| Rivulus kayabi Costa, 2008 | Melanorivulus kayabi | 76937 |
| Rivulus kayapo Costa, 2006 | Melanorivulus kayapo | 57725 |
| Moema kenwoodi Valdesalici, 2016 | Moema kenwoodi | 130458 |
| Rivulus kirovskyi Costa, 2004 | Laimosemion kirovskyi | 54752 |
| Rivulus kuelpmanni Berkenkamp & Etzel, 1993 | Cynodonichthys kuelpmanni | 36579 |
| Melanorivulus kunzei Costa, 2012 | Melanorivulus kunzei | 92338 |
| Plesiolebias lacerdai Costa, 1989 | Plesiolebias lacerdai | 36579 |
| Cynolebias lacortei Lazara, 1991 | Maratecoara lacortei | 57947 |
| Cynolebias ladigesi Foersch, 1958 | Notholebias minimus | 36579 |
| Rivulus lanceolatus Eigenmann, 1909 | Anablepsoides lanceolatus | 36579 |
| Rivulus lazzarotoi Costa, 2007 | Atlantirivulus lazzarotoi | 58743 |
| Melanorivulus leali Costa, 2013 | Melanorivulus leali | 94719 |
| Cynolebias leitaoi da Cruz & Peixoto, 1992 | Mucurilebias leitaoi | 95827 |
| Austrofundulus leohoignei Hrbek, Taphorn & Thomerson, 2005 | Austrofundulus leohoignei | 54496 |
| Austrofundulus leoni Hrbek, Taphorn & Thomerson, 2005 | Austrofundulus leoni | 54496 |
| Cynolebias leptocephalus Costa & Brasil, 1993 | Cynolebias leptocephalus | 36579 |
| Laimosemion leticia Valdesalici, 2016 | Laimosemion leticia | 130532 |
| Rivulus leucurus Fowler, 1944 | Cynodonichthys leucurus | 36579 |
| Rivulus limoncochae Hoedeman, 1962 | Anablepsoides limoncochae | 36579 |
| Melanorivulus linearis Costa, 2018 | Melanorivulus linearis | 116860 |
| Anablepsoides lineasoppilatae Valdesalici & Schindler, 2013 | Anablepsoides lineasoppilatae | 94121 |
| Rivulus litteratus Costa, 2005 | Melanorivulus litteratus | 54355 |
| Austrolebias litzi Costa, 2006 | Austrolebias litzi | 57613 |
| Simpsonichthys longignatus Costa, 2008 | Hypsolebias longignatus | 78710 |
| Pterolebias longipinnis Garman, 1895 | Pterolebias longipinnis | 57631 |
| Simpsonichthys lopesi Nielsen, Shibatta, Suzart & Martín, 2010 | Hypsolebias lopesi | 88806 |
| Austrolebias lourenciano Volcan, Barbosa, Robe & Lanés, 2021 | Austrolebias lourenciano | 129129 |
| Rivulichthys luelingi Meinken, 1969 | Pterolebias longipinnis | 57631 |
| Rivulus luelingi Seegers, 1984 | Atlantirivulus luelingi | 36579 |
| Anablepsoides luitalimae Nielsen, 2016 | Anablepsoides luitalimae | 128688 |
| Hypsolebias lulai Ramos, Nielsen, Abrantes, Lira & Lustosa-Costa, 2023 | Hypsolebias lulai | 130546 |
| Rivulus lungi Berkenkamp, 1984 | Anablepsoides lungi | 36579 |
| Cynolebias luteoflammulatus Vaz-Ferreira, Sierra de Soriano & Scaglia de Paulete, 1965 | Austrolebias luteoflammulatus | 27139 |
| Austrolebias luzardoi Perujo, Calviño, Salvia & Prieto, 2005 | Austrolebias periodicus | 57613 |
| Rivulus lyricauda Thomerson, Berkenkamp & Taphorn, 1991 | Laimosemion lyricauda | 36579 |
| Cynolebias mabelis Hoetmer, 1987 | Austrolebias affinis | 27139 |
| Laimosemion mabura Valdesalici & Gil-Garcia, 2015 | Laimosemion mabura | 119333 |
| Simpsonichthys macaubensis Costa & Suzart, 2006 | Hypsolebias macaubensis | 57610 |
| Trigonectes macrophthalmus Costa, 1990 | Trigonectes macrophthalmus | 36579 |
| Cynolebias maculatus Steindachner, 1881 | Austrolebias bellottii | 27139 |
| Pterolebias maculipinnis Radda, 1964 | Rachovia maculipinnis | 36579 |
| Rivulus magdalenae Eigenmann & Henn, 1916 | Cynodonichthys magdalenae | 36579 |
| Cynolebias magnificus Costa & Brasil, 1991 | Hypsolebias magnificus | 27139 |
| Rivulus mahdiaensis Suijker & Collier, 2006 | Laimosemion mahdiaensis | 57829 |
| Rivulus manaensis Hoedeman, 1961 | Laimosemion agilae | 36579 |
| Aphyolebias manuensis Costa, 2003 | Aphyolebias manuensis | 54621 |
| Simpsonichthys margaritatus Costa, 2012 | Simpsonichthys margaritatus | 89068 |
| Simpsonichthys marginatus Costa & Brasil, 1996 | Hypsolebias marginatus | 36579 |
| Atlantirivulus maricensis Costa, 2014 | Atlantirivulus maricensis | 102354 |
| Cynopoecilus marmoratus Ladiges, 1934 | Leptolebias marmoratus | 36579 |
| Rivulus marmoratus Poey, 1880 | Kryptolebias marmoratus | 36579 |
| Rivulus marmoratus bonairensis Hoedeman, 1958 | Kryptolebias marmoratus | 36579 |
| Hypsolebias martinsi Britzke, Nielsen & Oliveira, 2016 | Hypsolebias martinsi | 108434 |
| Rivulus mazaruni Myers, 1924 | Anablepsoides mazaruni | 36579 |
| Simpsonichthys mediopapillatus Costa, 2006 | Hypsolebias mediopapillatus | 57610 |
| Rivulus megaroni Costa, 2010 | Melanorivulus megaroni | 83423 |
| Cynolebias melanoorus Amato, 1986 | Austrolebias melanoorus | 27139 |
| Cynolebias melanotaenia Regan, 1912 | Cynopoecilus melanotaenia | 42931 |
| Cynolebias microphthalmus Costa & Brasil, 1995 | Cynolebias microphthalmus | 36579 |
| Fundulus micropus Steindachner, 1863 | Anablepsoides micropus | 26282 |
| Rivulus milesi Fowler, 1941 | Cynodonichthys magdalenae | 36579 |
| Cynolebias minimus Myers, 1942 | Notholebias minimus | 36579 |
| Austrolebias minuano Costa & Cheffe, 2001 | Austrolebias minuano | 44045 |
| Rivulus modestus Costa, 1991 | Melanorivulus modestus | 36579 |
| Rivulus monikae Berkenkamp & Etzel, 1995 | Cynodonichthys monikae | 36589 |
| Cynolebias monstrosus Huber, 1995 | Austrolebias monstrosus | 36579 |
| Rivulus monticola Staeck & Schindler, 1997 | Anablepsoides monticola | 26253 |
| Rivulus montium Hildebrand, 1938 | Cynodonichthys montium | 36579 |
| Cynopoecilus multipapillatus Costa, 2002 | Cynopoecilus multipapillatus | 42931 |
| Cynolebias multiradiatus Costa & Brasil, 1994 | Simpsonichthys multiradiatus | 49550 |
| Austrofundulus myersi Dahl, 1958 | Austrofundulus myersi | 54496 |
| Austrofundulus myersi (non Dahl, 1958) | Austrofundulus limnaeus | 54496 |
| Cynolebias myersi Carvalho, 1971 | Xenurolebias myersi | 96072 |
| Rivulus myersi Hubbs, 1936 | Cynodonichthys myersi | 36579 |
| Austrolebias nachtigalli Costa & Cheffe, 2006 | Austrolebias nachtigalli | 57613 |
| Cynolebias nanus da Cruz & Peixoto, 1983 | Leptolebias opalescens | 36579 |
| Rivulus nicoi Thomerson & Taphorn, 1992 | Laimosemion nicoi | 26619 |
| Simpsonichthys nielseni Costa, 2005 | Simpsonichthys nielseni | 56725 |
| Cynolebias nigripinnis Regan, 1912 | Austrolebias nigripinnis | 36579 |
| Austrolebias nigrofasciatus Costa & Cheffe, 2001 | Austrolebias nigrofasciatus | 44045 |
| Simpsonichthys nigromaculatus Costa, 2007 | Simpsonichthys nigromaculatus | 75131 |
| Melanorivulus nigromarginatus Costa, 2018 | Melanorivulus nigromarginatus | 116860 |
| Melanorivulus nigropunctatus Volcan, Klotzel & Lanés, 2017 | Melanorivulus nigropunctatus | 117357 |
| Cynopoecilus nigrovittatus Costa, 2002 | Cynopoecilus nigrovittatus | 42931 |
| Cynolebias nioni Berkenkamp, Reichert & Prieto, 1997 | Austrolebias nioni | 36579 |
| Hypsolebias nitens Costa, 2012 | Hypsolebias nitens | 89836 |
| Cynolebias nonoiuliensis Taberner, Fernández-Santos & Castelli, 1974 | Austrolebias nonoiuliensis | 46206 |
| Cynopoecilus notabilis Ferrer, Wingert & Malabarba, 2014 | Cynopoecilus notabilis | 98301 |
| Cynolebias notatus Costa, Lacerda & Brasil, 1990 | Hypsolebias notatus | 36579 |
| Austrolebias nubium Lanés, Volcan & Maltchik, 2021 | Austrolebias nubium | 123906 |
| Moema nudifrontata Costa, 2003 | Moema nudifrontata | 50838 |
| Hypsolebias nudiorbitatus Costa, 2011 | Hypsolebias nudiorbitatus | 88806 |
| Rivulus nudiventris Costa & Brasil, 1991 | Atlantirivulus nudiventris | 36579 |
| Pituna obliquoseriata Costa, 2007 | Pituna obliquoseriata | 57947 |
| Pterolebias obliquus Costa, Sarmiento & Barrera, 1996 | Aphyolebias obliquus | 26654 |
| Cynolebias obscurus Costa, 2014 | Cynolebias obscurus | 97357 |
| Rivulus obscurus Garman, 1895 | Anablepsoides ornatus | 36579 |
| Rivulus ocellatus Hensel, 1868 | Kryptolebias ocellatus | 52570 |
| Rivulus ocellatus (non Hensel, 1868) | Kryptolebias marmoratus | 27139 |
| Simpsonichthys ocellatus Costa, Nielsen & de Luca, 2001 | Simpsonichthys ocellatus | 30821 |
| Cynolebias ochraceus Costa, 2014 | Cynolebias ochraceus | 97357 |
| Melanorivulus ofaie Volcan, Klotzel & Lanés, 2017 | Melanorivulus ofaie | 117357 |
| Cynolebias opalescens Myers, 1942 | Leptolebias opalescens | 36579 |
| Rivulus ophiomimus Huber, 1992 | Anablepsoides ophiomimus | 36579 |
| Neofundulus ornatipinnis Myers, 1935 | Neofundulus ornatipinnis | 36579 |
| Rivulus ornatus Garman, 1895 | Anablepsoides ornatus | 36579 |
| Moema ortegai (non Costa, 2003) | Moema quiii | 110333 |
| Moema ortegai Costa, 2003 | Moema ortegai | 110333 |
| Renova oscari Thomerson & Taphorn, 1995 | Renova oscari | 36579 |
| Cynolebias oticus Costa, 2014 | Cynolebias oticus | 97357 |
| Anablepsoides ottonii Costa, Bragança & Amorim, 2013 | Anablepsoides ottonii | 94717 |
| Rivulus pacificus Huber, 1992 | Cynodonichthys pacificus | 36579 |
| Cynolebias pantanalensis Seegers, 1988 | Plesiolebias glaucopterus | 36579 |
| Nematolebias papilliferus Costa, 2002 | Nematolebias papilliferus | 42934 |
| Rivulus paracatuensis Costa, 2003 | Melanorivulus paracatuensis | 89845 |
| Cynolebias paraguassuensis Costa, Suzart & Nielsen, 2007 | Cynolebias paraguassuensis | 58745 |
| Fundulus paraguayensis Eigenmann & Kennedy, 1903 | Neofundulus paraguayensis | 36579 |
| Simpsonichthys parallelus Costa, 2000 | Simpsonichthys parallelus | 44211 |
| Austrolebias paranaensis Costa, 2006 | Austrolebias paranaensis | 57613 |
| Atlantirivulus paranaguensis Costa, 2014 | Atlantirivulus paranaguensis | 102354 |
| Cynolebias paranaguensis Myers, 1952 | Leptolebias aureoguttatus | 36579 |
| Rivulus paresi Costa, 2008 | Melanorivulus paresi | 76975 |
| Cynolebias parietalis Costa, 2014 | Cynolebias parietalis | 97357 |
| Rivulus parlettei Valdesalici & Schindler, 2011 | Anablepsoides parlettei | 88925 |
| Cynolebias parnaibensis Costa, Ramos, Alexandre & Ramos, 2010 | Cynolebias parnaibensis | 84460 |
| Rivulus parnaibensis Costa, 2003 | Melanorivulus parnaibensis | 89845 |
| Neofundulus parvipinnis Costa, 1988 | Neofundulus parvipinnis | 36579 |
| Laimosemion paryagi Vermeulen, Suijker & Collier, 2012 | Laimosemion paryagi | 92084 |
| Xenurolebias pataxo Costa, 2014 | Xenurolebias pataxo | 96072 |
| Cynolebias patriciae Huber, 1995 | Austrolebias patriciae | 27139 |
| Austrolebias paucisquama Ferrer dos Santos, Malabarba & Costa, 2008 | Austrolebias paucisquama | 76851 |
| Austrolebias pelotapes Costa & Cheffe, 2017 | Austrolebias pelotapes | 118050 |
| Moema pepotei Costa, 1993 | Moema pepotei | 36579 |
| Cynolebias perforatus Costa & Brasil, 1991 | Cynolebias perforatus | 36579 |
| Cynolebias periodicus Costa, 1999 | Austrolebias periodicus | 36579 |
| Simpsonichthys perpendicularis Costa, Nielsen & de Luca, 2001 | Simpsonichthys perpendicularis | 30821 |
| Haplochilus peruanus Regan, 1903 | Anablepsoides peruanus | 36579 |
| Pterolebias peruensis Myers, 1954 | Aphyolebias peruensis | 36579 |
| Rivulus peruensis Klee, 1965 | Anablepsoides peruanus | 27139 |
| Pterolebias phasianus Costa, 1988 | Pterolebias phasianus | 36579 |
| Simpsonichthys picturatus Costa, 2000 | Hypsolebias picturatus | 44211 |
| Rivulus pictus Costa, 1989 | Melanorivulus pictus | 54355 |
| Spectrolebias pilleti Nielsen & Brousseau, 2013 | Spectrolebias pilleti | 95105 |
| Melanorivulus pindorama Costa, 2012 | Melanorivulus pindorama | 91038 |
| Rivulus pinima (non Costa, 1989) | Melanorivulus pictus | 54355 |
| Rivulus pinima Costa, 1989 | Melanorivulus pinima | 54355 |
| Moema piriana Costa, 1989 | Moema piriana | 36579 |
| Rivulus pivijay Vermeulen, 2013 | Rivulus pivijay | 95022 |
| Rivulus planaltinus Costa & Brasil, 2008 | Melanorivulus planaltinus | 75171 |
| Rivulus poeyi Steindachner, 1876 | Anablepsoides urophthalmus | 36579 |
| Austrolebias pongondo Costa & Cheffe, 2017 | Austrolebias pongondo | 118117 |
| Pituna poranga (non Costa, 1989) | Pituna compacta | 57947 |
| Pituna poranga Costa, 1989 | Pituna poranga | 57947 |
| Cynolebias porosus Steindachner, 1876 | Cynolebias porosus | 97357 |
| Moema portugali Costa, 1989 | Moema portugali | 36579 |
| Cynolebias prognathus Amato, 1986 | Austrolebias prognathus | 36579 |
| Melanorivulus proximus Costa, 2018 | Melanorivulus proximus | 116860 |
| Hypsolebias pterophyllus Costa, 2012 | Hypsolebias pterophyllus | 89836 |
| Rivulus punctatus Boulenger, 1895 | Melanorivulus punctatus | 36579 |
| Simpsonichthys punctulatus Costa & Brasil, 2007 | Simpsonichthys punctulatus | 58746 |
| Rachovia pyropunctata Taphorn & Thomerson, 1978 | Rachovia pyropunctata | 36579 |
| Austrolebias queguay Serra & Loureiro, 2018 | Austrolebias queguay | 119404 |
| Moema quiii Huber, 2003 | Moema quiii | 110333 |
| Austrolebias quirogai Loureiro, Duarte & Zarucki, 2011 | Austrolebias quirogai | 87318 |
| Rivulus rachovii Ahl, 1925 | Atlantirivulus santensis | 36579 |
| Simpsonichthys radiosus Costa & Brasil, 2004 | Hypsolebias radiosus | 53226 |
| Hypsolebias radiseriatus Costa, 2012 | Hypsolebias radiseriatus | 89836 |
| Cynolebias rectiventer Costa, 2014 | Cynolebias rectiventer | 97357 |
| Rivulus rectocaudatus Fels & de Rham, 1981 | Laimosemion rectocaudatus | 36579 |
| Cynolebias regani Myers, 1952 | Cynolebias microphthalmus | 36579 |
| Cynolebias reicherti Loureiro & García, 2004 | Austrolebias reicherti | 57617 |
| Simpsonichthys reticulatus Costa & Nielsen, 2003 | Spectrolebias reticulatus | 52309 |
| Atlantirivulus ribeirensis Costa, 2014 | Atlantirivulus ribeirensis | 102354 |
| Rivulus ribesrubrum Vermeulen, 2013 | Rivulus ribesrubrum | 95022 |
| Rivulus riograndensis Costa & Lanés, 2009 | Atlantirivulus riograndensis | 81223 |
| Cynolebias robustus Günther, 1883 | Austrolebias robustus | 36579 |
| Cynolebias robustus (non Günther, 1883) | Austrolebias elongatus | 27139 |
| Rivulus robustus Miller & Hubbs, 1974 | Millerichthys robustus | 36579 |
| Rivulus rogoaguae Pearson & Myers, 1924 | Trigonectes rogoaguae | 36579 |
| Rivulus roloffi Roloff, 1938 | Rivulus roloffi | 36579 |
| Rivulus romeri Costa, 2003 | Laimosemion romeri | 54621 |
| Rivulus rondoni Miranda Ribeiro, 1920 | Trigonectes balzanii | 36579 |
| Anablepsoides roraima Costa, Bragança & Amorim, 2013 | Anablepsoides roraima | 94717 |
| Simpsonichthys rosaceus Costa, Nielsen & de Luca, 2001 | Simpsonichthys rosaceus | 30821 |
| Cynolebias roseus Costa, 2014 | Cynolebias roseus | 97357 |
| Rivulus rossoi Costa, 2005 | Melanorivulus rossoi | 54355 |
| Rivulus rubra Kramp, 1914 | Anablepsoides urophthalmus | 27139 |
| Pterolebias rubrocaudatus Seegers, 1984 | Aphyolebias rubrocaudatus | 27139 |
| Neofundulus rubrofasciatus Costa, 2015 | Neofundulus rubrofasciatus | 101435 |
| Rivulus rubrolineatus Fels & de Rham, 1981 | Anablepsoides rubrolineatus | 36579 |
| Rivulus rubromarginatus Costa, 2007 | Melanorivulus rubromarginatus | 59346 |
| Trigonectes rubromarginatus Costa, 1990 | Trigonectes rubromarginatus | 36579 |
| Melanorivulus rubroreticulatus Costa, Amorim & Bragança, 2014 | Melanorivulus rubroreticulatus | 96663 |
| Simpsonichthys rufus Costa, Nielsen & de Luca, 2001 | Simpsonichthys rufus | 30821 |
| Austrofundulus rupununi Hrbek, Taphorn & Thomerson, 2005 | Austrofundulus rupununi | 54496 |
| Rivulus rutilicaudus Costa, 2005 | Melanorivulus rutilicaudus | 54355 |
| Rivulus salmonicaudus Costa, 2007 | Melanorivulus salmonicaudus | 59346 |
| Austrolebias salviai Costa, Litz & Laurino, 2006 | Austrolebias reicherti | 79657 |
| Cynopoecilus sandrii Faria & Muller, 1937 | Leptolebias splendens | 27139 |
| Cynolebias santanae Shibatta & Garavello, 1992 | Simpsonichthys santanae | 27139 |
| Rivulus sape Lasso-Alcalá, Taphorn, Lasso & León-Mata, 2006 | Laimosemion sape | 57644 |
| Rivulus scalaris Costa, 2005 | Melanorivulus scalaris | 54355 |
| Pituna schindleri Costa, 2007 | Pituna schindleri | 57947 |
| Aphyolebias schleseri Costa, 2003 | Aphyolebias schleseri | 54621 |
| Rivulus schuncki Costa & De Luca, 2011 | Melanorivulus schuncki | 86535 |
| Spectrolebias semiocellatus Costa & Nielsen, 1997 | Spectrolebias semiocellatus | 93219 |
| Kryptolebias sepia Vermeulen & Hrbek, 2005 | Kryptolebias sepia | 53862 |
| Hypsolebias sertanejo Costa, 2012 | Hypsolebias sertanejo | 89836 |
| Hypsolebias shibattai Nielsen, Martins, de Araujo & dos Reis Suzart, 2014 | Hypsolebias shibattai | 94796 |
| Cynopoecilus sicheleri Miranda Ribeiro, 1939 | Leptolebias marmoratus | 50094 |
| Simpsonichthys similis Costa & Hellner, 1999 | Simpsonichthys similis | 36579 |
| Rivulus simplicis Costa, 2004 | Atlantirivulus simplicis | 55777 |
| Rivulus speciosus Fels & de Rham, 1981 | Anablepsoides speciosus | 36579 |
| Cynolebias spinifer Ahl, 1934 | Austrolebias elongatus | 36579 |
| Cynolebias splendens Myers, 1942 | Leptolebias splendens | 36579 |
| Rachovia splendens Dahl, 1958 | Rachovia brevis | 39689 |
| Maratecoara splendida Costa, 2007 | Maratecoara splendida | 57947 |
| Neofundulus splendidus Nielsen & Brousseau, 2013 | Neofundulus splendidus | 101435 |
| Hypsolebias splendissimus Costa, 2018 | Hypsolebias splendissimus | 119423 |
| Pterolebias staecki Seegers, 1987 | Moema staecki | 36579 |
| Rivulus staecki Schindler & Valdesalici, 2011 | Laimosemion staecki | 87326 |
| Austrofundulus stagnalis Schultz, 1949 | Austrofundulus limnaeus | 27139 |
| Rivulus stagnatus Eigenmann, 1909 | Anablepsoides stagnatus | 36579 |
| Cynolebias stellatus Costa & Brasil, 1994 | Simpsonichthys stellatus | 27139 |
| Rivulus stellifer Thomerson & Turner, 1973 | Llanolebias stellifer | 75238 |
| Trigonectes strigabundus Myers, 1925 | Trigonectes strigabundus | 36579 |
| Rivulus strigatus (non Regan, 1912) | Laimosemion geayi | 36579 |
| Rivulus strigatus Regan, 1912 | Laimosemion strigatus | 36579 |
| Simpsonichthys suzarti Costa, 2004 | Simpsonichthys suzarti | 53270 |
| Rivulus taeniatus Fowler, 1945 | Anablepsoides taeniatus | 36579 |
| Rivulus tecminae Thomerson, Nico & Taphorn, 1992 | Laimosemion tecminae | 26071 |
| Cynodonichthys tenuis Meek, 1904 | Cynodonichthys tenuis | 36579 |
| Rivulus tessellatus Huber, 1992 | Anablepsoides tessellatus | 36579 |
| Austrolebias toba Calviño, 2006 | Austrolebias toba | 57605 |
| Hypsolebias tocantinensis Nielsen, Cruz & Baptista, 2012 | Hypsolebias tocantinensis | 92140 |
| Rivulus tocantinensis Costa, 2010 | Anablepsoides tocantinensis | 84054 |
| Rivulus tomasi Vermeulen, Valdesalici & Garcia-Gil, 2013 | Rivulus tomasi | 94444 |
| Rivulus torrenticola Vermeulen & Isbrücker, 2000 | Laimosemion torrenticola | 36579 |
| Austrofundulus transilis Myers, 1932 | Austrofundulus transilis | 27139 |
| Austrofundulus transilis limnaeus Schultz, 1949 | Austrofundulus limnaeus | 26282 |
| Hypsolebias trifasciatus Nielsen, Martins, de Araujo, de Lira & Four, 2014 | Hypsolebias trifasciatus | 111470 |
| Cynolebias trilineatus Costa & Brasil, 1994 | Simpsonichthys trilineatus | 27139 |
| Rivulus uakti Costa, 2004 | Laimosemion uakti | 52792 |
| Rivulus uatuman Costa, 2004 | Laimosemion uatuman | 52555 |
| Laimosemion ubim Costa & Lazzarotto, 2014 | Laimosemion ubim | 95522 |
| Melanorivulus ubirajarai Costa, 2012 | Melanorivulus ubirajarai | 92338 |
| Rivulus unaensis Costa & De Luca, 2009 | Atlantirivulus unaensis | 81222 |
| Austrolebias univentripinnis Costa & Cheffe, 2005 | Austrolebias univentripinnis | 56780 |
| Rivulus uroflammeus Bussing, 1980 | Cynodonichthys uroflammeus | 36579 |
| Rivulus uroflammeus siegfriedi Bussing, 1980 | Cynodonichthys siegfriedi | 36579 |
| Rivulus urophthalmus Günther, 1866 | Anablepsoides urophthalmus | 36579 |
| Rivulus urophthalmus aurata Schreitmüller, 1919 | Anablepsoides urophthalmus | 42871 |
| Anablepsoides urubuiensis Costa, 2013 | Anablepsoides urubuiensis | 93231 |
| Cynolebias vandenbergorum Huber, 1995 | Austrolebias vandenbergorum | |
| Austrolebias varzeae Costa, Reis & Behr, 2004 | Austrolebias varzeae | 54764 |
| Cynolebias vazabarrisensis Costa, 2001 | Cynolebias vazabarrisensis | 40938 |
| Cynolebias vazferreirai Berkenkamp, Etzel, Reichert & Salvia, 1994 | Austrolebias vazferreirai | 27139 |
| Notholebias vermiculatus Costa & Amorim, 2013 | Notholebias vermiculatus | 98301 |
| Cynolebias viarius Vaz-Ferreira, Sierra de Soriano & Scaglia de Paulete, 1965 | Austrolebias viarius | 36579 |
| Anablepsoides vieirai Nielsen, 2016 | Anablepsoides vieirai | 128688 |
| Rivulus villwocki Berkenkamp & Etzel, 1997 | Cynodonichthys villwocki | 42871 |
| Rivulus violaceus Costa, 1991 | Melanorivulus violaceus | 36579 |
| Simpsonichthys virgulatus Costa & Brasil, 2006 | Simpsonichthys virgulatus | 57612 |
| Rivulus vittatus Costa, 1989 | Melanorivulus vittatus | 54355 |
| Rivulus vittatus (non Costa, 1989) | Melanorivulus pictus | 54355 |
| Rivulus vittatus (non Costa, 1989) | Melanorivulus apiamici | 54355 |
| Rivulus volcanus Hildebrand, 1938 | Cynodonichthys hildebrandi | 36579 |
| Rivulus waimacui Eigenmann, 1909 | Anablepsoides waimacui | 36579 |
| Melanorivulus wallacei Costa, 2016 | Melanorivulus wallacei | 128884 |
| Rivulus wassmanni Berkenkamp & Etzel, 1999 | Cynodonichthys wassmanni | 36579 |
| Rivulus weberi Huber, 1992 | Cynodonichthys weberi | 36579 |
| Cynolebias whitei Myers, 1942 | Nematolebias whitei | 36579 |
| Austrolebias wichi Alonso, Teran, Calviño, Garcia, Cardoso & Garcia, 2018 | Austrolebias wichi | 128060 |
| Pterolebias wischmanni Seegers, 1983 | Aphyolebias wischmanni | 27139 |
| Cynolebias wolterstorffi Ahl, 1924 | Austrolebias wolterstorffi | 57613 |
| Rivulus xanthonotus Ahl, 1926 | Anablepsoides xanthonotus | 36579 |
| Cynolebias xavantei Costa, Lacerda & Tanizaki, 1988 | Plesiolebias xavantei | 36579 |
| Rivulus xi Vermeulen, 2013 | Rivulus xi | 95022 |
| Pituna xinguensis Costa & Nielsen, 2007 | Pituna xinguensis | 57947 |
| Rivulus xinguensis Costa, 2010 | Anablepsoides xinguensis | 84054 |
| Rivulus xiphidius Huber, 1979 | Laimosemion xiphidius | 36579 |
| Pterolebias xiphophorus Thomerson & Taphorn, 1992 | Micromoema xiphophora | 36579 |
| Cynolebias zingiberinus Myers, 1942 | Leptolebias marmoratus | 36579 |
| Cynolebias zonatus Costa & Brasil, 1990 | Simpsonichthys zonatus | 36579 |
| Pterolebias zonatus Myers, 1935 | Pterolebias zonatus | 13284 |
| Rivulus zygonectes Myers, 1927 | Melanorivulus zygonectes | 36579 |