This study aimed to evaluate the nutritive value, growth parameters, productivity and economical efficiency of dried blue green algae for feeding Nile tilapia (Oreochromis niloticus) cultured in rice fields. Eight rice fields (one fed. each) were cultivated by rice and divided into four groups, the first group (Ti) of two fields with dried blue green algae at a rate of 5% of body weight per week, and the second (T2) one was fed on artificial diet containing 20% crud protein. The third group (T3) was fed on natural food resulting from fertilization only (30 Kg. chicken manure/week) and the fourth group (T4) has served as a control (without any treatment).All fields were stocked with Nile tilapia (1000 fingerlings/fed.) with an average weight of 30 g. The growing season for tilapia fish was 90 days. Results obtained can be summarized in the following:
- Treatments applied had sigpificant effect on final body weight, specific growth rate, body length and condition factor of Nile tilapia.
- The highest survival rate was obtained with group of fish on T2 followed by Ti^T* treatments respectively
- The highest net production was recorded with group offish on T2 followed by Ti, T3 and T4 treatments respectively.
- The highest net return was recorded with group of fish on Ti followed by T3, T2 and T4 treatments respectively.