Aquaculture, the process of raising aquatic animals in ponds, is gaining more attention in recent times. The feeding system is an important aspect of aquacultural practice. A simple, relatively inexpensive automatic fish feeder was designed, constructed and evaluated. The operation of the feeder does not require highly technical expertise. This paper reports the design considerations, materials used and the effectiveness of the device, based on analysis of manual feeding and automatic feeding. The main features of the device are: hopper (stainless steel), bi-directional motor, feed platform and electrical control box. The design was based on specific parameters which included capacity of culture tank, stocking density, fish biomass, diameter of the feed, angle of repose and bulk density (of the feed). The total cost of the device was 17,000 naira (approx. 106 U.S. dollars). The device was tested under two culture tanks (0.75 m 3 each) with 10 kg-33 juvenile cat fish (Clarias gariepinus) placed in each tank with one feeding automatically and the other, manually. The feeder evaluation was based on feed conversion ratio (FCR) and feeding efficiency (FE).The total average gain in weight per fish was higher in the automatic feeding (89.50 g) than in manual (78.50 g). An FE of 20.9% was obtained in the automatic feeding and 18.6% in manual, in relation to their FCRs. A t-test, conducted at 5% significance level, indicated a significant difference in the two feeding methods.