Photobacterium damselae subsp. piscicida (Pdp) is characterised by high infectivity and mortality and wide distribution, resulting in substantial economic losses to the global aquaculture industry. Therefore, it is critical to develop a simple, rapid and accurate diagnostic method for Pdp detection. Herein, two Pdp-specific monoclonal antibodies (mAbs 1H7 and 6E6) were obtained, indirect enzyme-linked immunosorbent assay and immunofluorescence analysis confirmed that the mAbs specifically recognised the outer membrane of Pdp but could not recognise the other Gram-positive or Gram-negative bacteria, indicating good specificity. A colloidal gold immunochromatographic strip (CGICS) was developed here for Pdp detection by optimising the colloidal gold labeling and antibody coating conditions using 1H7 as a colloidal gold-labelled antibody and 6E6 as a coated antibody. The CGICS exhibited a detection limit of 1 × 10