Poor nutritional quality of complementary foods often limits growth. Animal source foods, such as milk or meat, are often unaffordable. Local affordable alternatives are needed. We evaluate the efficacy of 2 newly developed, rice-based complementary food products: WinFood (WF) with small fish and edible spiders and WinFood-Lite (WF-L) fortified with small fish, against 2 existing fortified corn-soy blend products, CSB+ (purely plant based) and CSB++ (8% dried skimmed milk). In total, 419 infants aged 6 mo were enrolled in this randomized, single-blinded study for 9 mo, designed primarily to assess increments in fat-free mass by a deuterium dilution technique and change in plasma ferritin and soluble transferrin receptor. Secondary endpoints were changes in anthropometric variables, including knee-heel length. Data were analyzed by the intention-to-treat approach. There was no difference in fat-free mass increment in WF or WF-L compared with CSB+ [WF: +0.04 kg (95% CI: -0.20, 0.28 kg); WF-L: +0.14 kg (95% CI: -0.10, 0.38 kg)] or CSB++ [WF: -0.03 kg (95% CI: -0.27, 0.21 kg); WF-L: +0.07 kg (95% CI: -0.18, 0.31 kg)] and no effect on iron status. The 1.7-mm (95% CI: -0.1, 3.5 mm) greater increase in knee-heel length in WF-L than in CSB+ was not significant. No difference was found between the locally produced products (WF and WF-L) and the CSBs. Micronutrient fortification may be necessary, and small fish may be an affordable alternative to milk to improve complementary foods. The dietary role of edible spiders needs to be further explored. This trial was registered at controlled-trials.com as ISRCTN19918531.