<div style="text-align:justify">Background: External factors affecting the embryonic development of fishes have importance in aquaculture and conservational studies. The temperature directly affects the development rate and hatching success of fish eggs. An optimum level of temperature is required for each species for the highest hatching rate and proper development. The Nilgiri melon barb Haludaria fasciata is an indigenous ornamental fish of India and this study aims to find the effect of temperature on its embryonic development and find the optimum temperature for hatcheries. 
Methods: The H. fasciata were bred in a controlled condition and fertilized eggs were selected for the study. The embryonic development stages were observed under a digital microscope. The eggs were incubated at different temperatures ranging from 10 to 35&deg;C to find their effect on embryonic development on achieving each stage and hatching success. 
Result: Among the temperature, the eggs incubated at 35&deg;C have developed and hatched earlier (within 23 hrs 50 min&plusmn;3 min) than in other treatments. The slowest development and late hatching (within 29 hrs 20 min&plusmn;14 min) were observed at 20&deg;C. At 26&deg;C, the incubated eggs had a higher hatching rate and higher survival rate (97.68%). Based on the observations, it is suggested fish hatcheries incubate the eggs of H. fasciata at 26&deg;C for attaining better production.</div>

Effect of Temperature on the Embryonic Development of Nilgiri Melon Barb Haludaria fasciata