The food and feeding habits of Nile tilapia (Oreochromis niloticus) in ponds received inorganic fertilizer with different ratios of N:P:K were studied. The ratios were 20:20:5,20:40:5, and 20:20:0 and applied at a rate of 40 kg/feddan/month. It was found that, 0.mloticus mainly con­sumed phytoplankton. The main items found in fish stomach belonged to Cyanophyta, Chlorophyta, Bacillanophyta and Euglenophyta. Detritus consisted mainly of scraps of macrophytes and mud. Zooplankton was occasionally found. The most frequently species represented in the food were Anabaena spp., Mensmopedia eleganse, Microcystas aeruginosa, Os­cillatona spp. and Spruhna sp. (Cyanophyta). Ch/Dregs spp., Pandonha morum, Pediastrum spp. Scenedesmus spp. and Shereoderia setigera (Chlorphyta), Amphora ovahs, Gyrostgma attenuatum, Melosira granulate, Navicula map., Nitzschia spp., Pin/J/aria spp. and Synedra sp. (Bacillanophyta) and Euglena spp. and Phacus spp. (Euglenophyta). 0.nthaticus could select only Cyanophyta and Euglenophyta dunng the in­vestigation period and sometimes select Bacillanophyta.