Improving the survival and growth of African catfish (Clarias gariepinus) fingerlings by using Nile tilapi

In an attempt to improve the survival rate of African catfish, <i>Clarias gariepinus</i> fingerlings, an experiment was conducted in six cement ponds (15 m3 per each). African catfish were cultured with Nile tilapia, <i>Oreochromis niloticus </i>as species combination at three different ratios with two replicates. Each pond was stocked by 40 <i>O. niloticus</i> (7.8 ± 1.3 g), meanwhile 40, 30 and 20 C. gariepinus (8.9 ± 1.7 g) were stocked at group 1, 2 and 3 for 10 weeks. Fish were fed for satiation on 30%-protein diet twice daily; five days a week for 10 weeks. At the end of the experiment, ponds were drained and fish were harvested, counted, and weighed. The catfish were classified by weight to four classes; class 1 (20-25 g), class 2 (25-30 g), class 3 (30-40 g), and class 4 (40-50 g). Growth performances of both fishes were significantly differenced among the different groups. The best growth for <i>C. gariepinus</i> and <i>O. niloticus</i> was recorded in groups 2 and 1, respectively.  No significant difference in <i>C. gariepinus</i> length was recorded, while <i>O. niloticus</i> length was significantly differed (P>0.05) between treatment 1 and other treatments. <i>C. gariepinus</i> classes were significantly differed among the different fish groups. Among the different groups no significant differences in catfish survival (80-85%), while it was significantly differed in tilapia (89.9-98.3%). The results of the present study showed that using <i>O. niloticus</i> fingerlings has a positive impact on <i>C. gariepinus</i> growth and survival rate and it could be recommended using <i>O. niloticus</i> in <i>C. gariepinus</i> culture as a technique to minimize their cannibalism. Minimizing the use of grading and sorting of catfish which lead to avoid the stress resulting from their use on African catfish Clarias gariepinus and reduce the production costs