Two trials were undertaken to evaluate the potential for using the aquatic weed Ceratophyllum sp. as a feed source for tilapia (Oreochromis niloticus) culture in brackishwater ponds. The trials were undertaken in a brackishwater pond (salinity <18 ppt) in Aceh, Indonesia. In both trials Ceratophyllum was fed to tilapia in 10 m 10 m hapas in the pond and growth and productivity parameters compared with the unfed control fish. In the second trial, pellet feed was also compared as a feed source. The results showed that tilapia fed Ceratophyllum at the rate of 2 kg (wet weight) per day were 12–23% larger than the unfed controls at 115–120 days of culture. Although the fish fed pellets were 45% larger than the controls, the cost of the pellet feed makes this option economically unattractive.