The invention relates to a copper alloy, composed of (in wt %): 51.8 to 84.0% Cu, 15.5 to 36.0% Zn, 0.35 to 3.0% Sn, 0.12 to 1.5% Fe, 0.02 to 1.0% P, optionally also 0.1 to 2.0% Al, optionally also 0.05 to 0.7% Si, optionally also 0.05 to 2.0% Ni, optionally also respectively 0.1 to 1.0% Mn, Co, optionally also respectively 0.01 to 1.0% As, Sb, and unavoidable contaminants, wherein more than 95% of the structure consist of α-mixed crystal, in which at least iron phosphides and/or iron are embedded as deposition particles, which can be used for metallic articles in breeding organisms living in seawater.