Gene co-expression modules SK1 and SK6, enriched for adaptive immune responses (SK1; e.g. klhl6, trpm4) and wound healing processes (SK6; e.g. cask, Additional file 7), were negatively correlated with infection status and positively associated with density, indicating a lower level of immunosuppression in the skin of high density fish. The gene discussed is CASK; the disease is infection.