The research was conducted to investigate the growth performance of Oreochromis niloticus fingerlings and plankton production in earthen ponds located at 2,500 msl, 2,100 msl and 1,710 msl in the west shoa zone, Ethiopia. The stocking density of each pond was 2/m². The initial average length and weight of the fingerlings were 5±0.03 cm and 5.7±0.02 gm, respectively. The study has been conducted for a period of 120 days (October 2011-February 2012). Before stocking, the ponds were treated with quicklime (0.05 kg/m²) and fertilized with cow manure (0.1 kg/m²/week). Supplementary feed (wheat bran and nuog cake)was provided at the rate 3% of body weight throughout the growing period. Growth measurements were recorded at 15 days interval. The results showed that the final weight of O. niloticus was 18.2±0.02, 52.4±0.97 and 63.7±0.50 g at the altitude of 2,500 msl, 2,100 msl and 1,710 msl, respectively. The average daily body weight gain was 0.2±0.00, 0.7±0.05 and 0.8±0.04 gm in 2,500 msl, 2,100 msl and 1,710 msl, respectively. Survival rate was higher at the altitude of 1,710 msl. Moreover, specific growth rate, average feed conversion ratio, condition of fish, plankton abundance and distribution were significantly (P<0.05) varied in the three altitude ponds.