Development of a sandwich vertical flow immunogold assay for rapid detection of oxytetracycline residue in fish tissues

•Development, comparison and validation of silver enhanced, multiplex sandwich vertical flow immunogold assay (SVIA) for sensitive and rapid detection of OTC residues in edible fish tissues.•Combining silver enhancement with immunogold labelled MAb improved the sensitivity.•Employing anti-OTC capture rabbit antiserum and detector monoclonal antibody provided high specificity with a visual detection limit of 2 ng mL−1.•It is a semi-quantitative, simple, rapid, low cost assay compatible with field level analysis.