The present study was carried out to find the most suitable fish species for stocking in rice field as well as selection the optimum fry size in this integration system. Two rice fields (4 feddans for each area) were stocked with fish as integration system. The first field stocked with 10000 fingerlings of Nile tilapia Oreochromis niloticus (2500 fingerlings/feddan) and the second field was stocked with 6000 fingerlings of common carp Cyprinus carpio (1500 fingerlings/feddan). The obtained results can be summarized as follows:
- The average body weight of O. niloticus increased from 26.2 g at the experimental start to 176.8 g at the end of the experiment with daily weight gain ranged from 0.54 to 2.08 g and the body length increased from 10.8 cm at the experimental start to 21.6 cm at the end of the experiment.
- The average body weight of Cyprinus carpio increased also from 11.7 at the experimental start to 154.5 g at the end of the experiment with daily weight gain ranged from 0.46 to 2.02 g and the body length increased from 6.9 at the experimental start to 20.4 cm at the end of the experiment.
- Specific growth rate (SGR) ranged from 0.81 to 2.69 for O. niloticus and 1.65 to 2.58 for Cyprinus carpio.