Species described (92):
- Agosia chrysogaster Girard, 1856 (Agosia), valid
- Agosia metallica Girard, 1856, synonym
- Algoma fluviatilis Girard, 1856, synonym
- Alvarius lateralis Girard, 1859, synonym
- Amblodon neglectus Girard, 1858, synonym
- Anguilla tyrannus Girard, 1858, synonym
- Argyreus notabilis Girard, 1856, synonym
- Boleichthys elegans Girard, 1859, synonym
- Bryttus signifer Girard, 1858, synonym
- Calliurus diaphanus Girard, 1858, synonym
- Calliurus formosus Girard, 1858, synonym
- Calliurus microps Girard, 1858, synonym
- Calliurus murinus Girard, 1858, synonym
- Campostoma formosulum Girard, 1856, synonym
- Campostoma nasutum Girard, 1856, synonym
- Campostoma ornatum Girard, 1856 (Campostoma), valid
- Catostomus (Acomus) generosus Girard, 1856, synonym
- Catostomus (Acomus) guzmaniensis Girard, 1856, synonym
- Catostomus bernardini Girard, 1856 (Catostomus), valid
- Catostomus (Acomus) generosus Girard, 1856, synonym
- Codoma ornata Girard, 1856 (Codoma), valid
- Codoma vittata Girard, 1856, synonym
- Cyprinella formosa Girard, 1856 (Cyprinella), valid
- Cyprinella gunnisoni Girard, 1856, synonym
- Cyprinella laetabilis Girard, 1856, synonym
- Cyprinella ludibunda Girard, 1856, synonym
- Cyprinella notata Girard, 1856, synonym
- Moniana proserpina Girard, 1856 (Cyprinella), valid
- Moniana rutila Girard, 1856 (Cyprinella), valid
- Cyprinella suavis Girard, 1856, synonym
- Cyprinella umbrosa Girard, 1856, synonym
- Cyprinella venusta Girard, 1856 (Cyprinella), valid
- Cyprinodon californiensis Girard, 1859, synonym
- Cyprinodon eximius Girard, 1859 (Cyprinodon), valid
- Dionda couchi Girard, 1856, synonym
- Dionda episcopa Girard, 1856 (Dionda), valid
- Dionda melanops Girard, 1856 (Dionda), valid
- Dionda plumbea Girard, 1856, synonym
- Dionda spadicea Girard, 1856, synonym
- Diplesion fasciatus Girard, 1859, synonym
- Oligocephalus grahami Girard, 1859 (Etheostoma), valid
- Aplesion pottsii Girard, 1859 (Etheostoma), valid
- Gobius lyricus Girard, 1858 (Evorthodus), valid
- Fundulus floridensis Girard, 1859, synonym
- Fundulus parvipinnis Girard, 1854 (Fundulus), valid
- Gambusia holbrooki Girard, 1859 (Gambusia), valid
- Gambusia humilis Girard, 1859, synonym
- Gambusia senilis Girard, 1859 (Gambusia), valid
- Gambusia speciosa Girard, 1859 (Gambusia), valid
- Tigoma intermedia Girard, 1856 (Gila), valid
- Tigoma nigrescens Girard, 1856 (Gila), valid
- Tigoma purpurea Girard, 1856 (Gila), valid
- Tigoma purpurea Girard, 1856 (Gila), valid
- Algoma amara Girard, 1856 (Hybognathus), valid
- Hyborhynchus confertus Girard, 1856, synonym
- Hyborhynchus puniceus Girard, 1856, synonym
- Pimelodus lupus Girard, 1858 (Ictalurus), valid
- Lepisosteus (Atractosteus) berlandieri Girard, 1858, synonym
- Lepisosteus (Cylindrosteus) latirostris Girard, 1858, synonym
- Lepisosteus leptorhynchus Girard, 1858, synonym
- Leptocottus armatus Girard, 1854 (Leptocottus), valid
- Limia matamorensis Girard, 1859, synonym
- Limia poeciloides Girard, 1858, synonym
- Limia venusta Girard, 1858, synonym
- Lucania affinis Girard, 1859, synonym
- Meda fulgida Girard, 1856 (Meda), valid
- Megalops elongatus Girard, 1859, synonym
- Moniana aurata Girard, 1856, synonym
- Moniana complanata Girard, 1856, synonym
- Moniana couchi Girard, 1856, synonym
- Moniana frigida Girard, 1856, synonym
- Moniana gibbosa Girard, 1856, synonym
- Moniana gracilis Girard, 1856, synonym
- Moniana leonina Girard, 1856, synonym
- Moniana pulchella Girard, 1856, synonym
- Ptychostomus albidus Girard, 1856 (Moxostoma), valid
- Moxostoma campbelli Girard, 1856, synonym
- Alburnus amabilis Girard, 1856 (Notropis), valid
- Pimelodus confinis Girard, 1859, synonym
- Pimelodus cupreoides Girard, 1859, synonym
- Pimelodus graciosus Girard, 1859, synonym
- Pimelodus houghi Girard, 1859, synonym
- Pimephales fasciatus Girard, 1856, synonym
- Pimephales maculosus Girard, 1856, synonym
- Limia formosa Girard, 1859 (Poecilia), valid
- Poecilia lineolata Girard, 1858, synonym
- Girardinus sonoriensis Girard, 1859 (Poeciliopsis), valid
- Ptychocheilus lucius Girard, 1856 (Ptychocheilus), valid
- Ptychocheilus vorax Girard, 1856, synonym
- Argyreus osculus Girard, 1856 (Rhinichthys), valid
- Tiaroga cobitis Girard, 1856 (Tiaroga), valid
- Limia couchiana Girard, 1859 (Xiphophorus), valid
Genera described (11):
- Agosia Girard, 1856, valid
- Algansea Girard, 1856, valid
- Codoma Girard, 1856, valid
- Cyprinella Girard, 1856, valid
- Dionda Girard, 1856, valid
- Gobionellus Girard, 1858, valid
- Gobiosoma Girard, 1858, valid
- Leptocottus Girard, 1854, valid
- Lucania Girard, 1859, valid
- Meda Girard, 1856, valid
- Tiaroga Girard, 1856, valid