Compared to the most active anion-transporting channel that requires a channel:lipid molar ratio of 1:330 (0.3 mol % relative to lipid) to achieve 50% activity, a structurally simple pore-forming tripeptide 6L310 was found to exhibit an extraordinarily strong ability to self-assemble into stable possibly barrel-shaped exceptionally active channels, with record-low EC50 values of 4.0, 3.0, 1.6, 2.6, and 2.6 nM (e.g., 0.005-0.013 mol % relative to lipid) for Cl-, Br-, I-, NO3-, and ClO4-, respectively.