The two fish species Betta splendens (Regan) and Poecilia reticulata (Peters) are known predators of Aedes aegypti (L., 1762) larvae. Both species have been used for biological control in northeastern Brazil. However, the feasibility of these fish for the control of Ae. aegypti larvae in domestic containers may be limited by their survival in chlorinated water, as supplied by the public water system. We exposed fish to three different concentrations of chlorine: 1, 1.5, and 2.0 mg/liter. All B. splendens survived at 1.0 mg/liter chlorine concentration; 72.5 and 39.3% of B. splendens survived chlorine concentrations of 1.5 and 2.0 mg/liter, respectively. In contrast, only 4.4% of P. reticulata survived at a chlorine concentration of 1.0 mg/liter. We conclude that B. splendens may be an appropriate species for biological control of Ae. aegypti in domestic water tanks.