Summary Aeromonas hydrophila is an opportunistic Gram‐negative pathogen that readily attaches to stainless steel to produce a thin biofilm with a complex 3D structure covering 40–50% of the available surface and producing large microcolonies. As A. hydrophila possesses an N ‐acylhomoserine lactone (AHL)‐dependent quorum‐sensing system based on the ahyRI locus, the presence of the AhyI protein and C4‐HSL within the biofilm phas...