This paper deals with the spawning time of the Teleostean fishes based on various published data. From the viewpoint of the spawning time, fishes can be generally classified into four types as follows. A) Species spawning at night, especially during the period from evening twilight to midnight. B) Species spawning in the daytime, especially from the dawn to the early morning. C) Species spawning in relation to the tides, i.e., spawning mostly at the high tide in the highest flood-tide. D) Species without any specific spawning time. Clupeida-fishes mostly belong to the first type, while many fresh-water species of Cyprinida belong to the second. Some inshore fishes may fall into the third. Only a few species are included in the fourth type (Table 1). The light seems to be an important factor affecting the impulse of fish-spawning, the time of which is more or less fixed by each species. But it is hard to say that each species had obtained such habit of the regular-time-spawning by the influence of the present environment as there are several facts which can be considered only by the phylogenetical viewpoint of these fishes.
