Abstract: The diurnal feeding rhythm and the daily feeding amount were measured for the15-day old larval Taiwan loach(Paramisgurnus sp. )(which could be local population or genetic improvement group of Paramisgurnus dabryanus) in natural light, continuous light and dark condition respectively. The results of feeding rhythm and daily feeding amount of15- day larvae under natural illumination, successive illumination, and successive darkness showed that: all the tested larvae were found to have a typical daytime feeding rhythm, and fed actively during9:00-18:00 under natural illumination, successive illu- mination. The feeding intensity under successive dark was only48. 6% of the feeding amount under natural illumination. There was no significant difference in terms of the feeding intensity during9:00-18:00 under natural illumination and successive illu- mination. The feeding intensity increased in continuous light group was higher than that of the control group at6 :00 a. m. and 21:00 p. m. In the continuous light group, the daily feeding amount increased by10. 66 % compared with that of control group. Under successive dark, the daily feeding amount decreased to53. 62% of the amount found in control group. The feed- ing rhythm of the15-day Taiwan loach is of a daytime type dependant on visual and sensory organs and their feeding intensity is strongly affected by the illumination.