author(s)
Sambid Swain, Paromita Banerjee Sawant, Narinder Kumar Chadha, JK Sundaray and Chandra Prakash

abstract
The study was conducted to determine the influence of varying incubating water pH of 5.26 ± 0.14, 6.60 ± 0.12, 7.36 ± 0.08, 8.60 ± 0.15 on hatching percentage, incubation period, survival and initial egg development of discus, Symphysodon aequifasciatus. The study illustrated that discus eggs required a water pH between 5.26 to 8.60 for hatching. The egg incubated at acidic pH had smaller eggs diameter compared to alkaline pH treatments. Highest embryonic survival was recorded at pH 6.60. It can be noted that there is a profound influence of incubation water pH on the embryonic stage as it influences from cleavage stage till eclosion, the eggs incubated in acidic pH developed faster than those incubated in alkaline pH from cleavage stage till successful hatching. It can be concluded that pH affects the initial eggs development and pH 6.60 can be considered best for discus egg development with minimum incubation duration and highest survival along with high hatching percentage, which can be helpful to promote successful hatchery operation.