| The Skeleton of Lepidosteus, with remarks on the origin and evolution of the lower Neopterygian Fishes CT Regan Proceedings of the Zoological Society of London 93 (2), 445-461, 1923 | 231 | 1923 |
| III. A Monograph of the Fishes of the Family Loricariidæ. CT Regan The Transactions of the Zoological Society of London 17 (3), 191-350, 1904 | 223 | 1904 |
| LXV.—The classification of the Teleostean fishes of the order Ostariophysi.—2. Siluroidea CT Regan Journal of Natural History 8 (47), 553-577, 1911 | 185 | 1911 |
| THE ANNALS CT REGAN The Annals and Magazine of Natural History: Zoology, Botany, and Geology, 265, 1912 | 183 | 1912 |
| II.—The classification of the teleostean fishes of the order Ostariophysi.—1. Cyprinoidea CT Regan Annals and Magazine of Natural History 8 (43), 13-32, 1911 | 182 | 1911 |
| II.—The Antarctic Fishes of the Scottish National Antarctic Expedition CT Regan Earth and Environmental Science Transactions of The Royal Society of …, 1913 | 181 | 1913 |
| The freshwater fishes of the British Isles CT Regan Methuen & Company, 1911 | 141 | 1911 |
| A Revision of the Cyprinodont Fishes of tho Subfamily Pœciliinæ. CT Regan Proceedings of the Zoological Society of London 83 (4), 977-1018, 1913 | 140 | 1913 |
| No. XIV.–Report on the marine fishes collected by Mr. J. Stanley Gardiner in the Indian Ocean. CT Regan Trans Linn Soc London Zool Ser 2 (12), 217-255, 1908 | 136 | 1908 |
| XVII.—The classification of the Percoid fishes CT Regan Annals and Magazine of Natural History 12 (67), 111-145, 1913 | 134 | 1913 |
| A classification of the selachian fishes CT Regan | 131 | 1906 |
| XV. Pisces CT Regan The Zoological Record 50, 1-44, 1914 | 121 | 1914 |
| III.—The classification of the fishes of the family Cichlidae.—I. The Tanganyika genera CT Regan Annals and Magazine of Natural History 5 (25), 33-53, 1920 | 112 | 1920 |
| Organic evolution CT Regan Nature 116 (2915), 398-401, 1925 | 111 | 1925 |
| The fishes of the families Stomiatidae and Malacosteidae T Regan, E Trewavas Brill, 2024 | 89 | 2024 |
| VII.—A Revision of the Fishes of the American Cichlid Genus Cichlosoma and of the Allied Genera CT Regan Journal of Natural History 16 (91), 60-77, 1905 | 89* | 1905 |
| XII.—The classification of Teleostean fishes CT Regan Annals and Magazine of Natural History 3 (13), 75-86, 1909 | 88 | 1909 |
| Deep-sea angler fishes T Regan Deep-sea angler fishes, 1932 | 80 | 1932 |
| LIV.—the origin and evolution of the Teleostean fishes of the order Heterosomata CT Regan Annals and Magazine of Natural History 6 (35), 484-496, 1910 | 80 | 1910 |
| The Asiatic fishes of the family Anabantidae CT Regan Proceedings of the Zoological Society of London 1910 (pt 4), 767-787, 1909 | 78 | 1909 |
