Mystus cavasius, an important catfish is acceptable by aquaculturists as a desired candidate species for aquaculture due to high market demand. The uncertain seed availability from natural water compels for its captive production. Hence the present article communicates the optimum stocking density of larvae and fry during its hatchery production. The catfish was induced bred and seed were reared in hatchery to get the stocking material for the experiment. The larvae of 4 days old were utilised for larval density experiment. Larvae were reared for 21 days at 5, 10, 15 and 20 larvae L⁻¹ to ascertain the optimum stocking density necessary for larval rearing. Similarly, the fry of 21 days old were stocked at densities of 50, 100, 200, 300 and 400 fry m-2 and reared for 8 week experimental period. The larval rearing at 5 larvae L-1 showed significantly higher (p<0.05) growth (23mg) and survival (79%) as compared to three other density trials. The decrease of growth and survival with the increase of density during larval rearing indicated for a low density larval rearing at initial stage. However, the density of 10 larvae L⁻¹ may be accepted as this density level performs more than 50% survival to get a higher number of fry during hatchery production. The growth and survival of fry was also in descending order as the density increased. The highest ((p<0.05) growth and survival was exhibited while stocking 50 fry m-2. The study also revealed that the survival per cent was more than 90% while rearing at 100 fry m-2. Hence the present study recommends a low stocking density rearing of this catfish at larval and fry stage. The results also cautioned to adopt a maximum density level of 10 larvae L⁻¹ and 100 fry m-2 to get higher number of seed, beyond which the growth and survival rate will be affected at larval and fry stage.