Predicted to enable copper ion transmembrane transporter activity. Acts upstream of or within cellular response to estrogen stimulus; hypotonic salinity response; and response to copper ion. Predicted to be located in apical plasma membrane; basolateral plasma membrane; and endosome membrane. Is expressed in gill; gut; liver; locus coeruleus; and yolk syncytial layer. Orthologous to human SLC31A1 (solute carrier family 31 member 1).