Cage culture of Penaus indicus in Vellar estuary was carried out by feeding the prawns with M/S ruminant pelleted feed at the rate of 10%of body weight in the first month and 15%of body weight in the remaining culture period. The environmental parameters viz. temperature, salinity, dissolved oxygen and hydrogen ion concentration were monitored and were found to be ranged from 27-30^oC, 2.1-34.1%_0, 3.0-4.5ml/l and 8.0-8.7 respectively. The prawn seeds of  39.0 to 41.0 mm length and 0.41 to 0.52 gm weight were stocked at the rate of 240 seeds/ 20 m². The final length and weight of the prawns were ranging from 120 to 125 mm and 13.0 to 13.5 gm respectively. The growth rate was calculated and it was 1.76 mm/day and 0.279 gm/day in terms of length and weight respectively  The length weight relationship has been studied and was found that the result is obeying the cube law and the correlation coefficient was 0.98 which is highly significant at 5% level. The total harvest was 3.7 kg/ 20 m²/ 90 days  and (1975 kg/ha/90 days) with 100% survival. The autoentrants (Penaeus indicus, Penaeus monodon, Metapenaeus spp., Macrobrachium sp., Gerres sp. and Terapon sp.) contributed 0.25 kg in the total harvest.