Effect of Lunar Synchronization on the Reproduction Time of Discus Fish (Symphysodon sp.) Under Controlled Aquarium Conditions

The reproduction times of the discus fish were observed for 2 years under fully-controlled production conditions. The position of the moon was also recorded on the spawning day of the fish at a light photoperiod of 14 h and a dark photoperiod of 10 h with water quality parameters of 27-30 degrees C, pH 4.5-6.5 and conductivity of 80-200 mu S. Of 102 observed reproductions, 28 occurred at the first quarter of the moon, 28 at full moon, 40 at the last quarter and 6 at new moon. Accordingly, it has been concluded that the discus fish display a reproduction behavior according to the lunar cycle even indoors, although they do not receive direct moonlight.