Polyvinyl chloride (PVC) microplastics may compromise fish health, but visible sublethal responses in ornamental fish remain poorly documented. This study evaluated whether nominal PVC microplastic exposure altered CIE L*a*b* body-colour indices, Fulton's condition factor, and survival of guppy (Poecilia reticulata). A completely randomized design included 0, 5, 15, and 20 mg/L PVC treatments, each with three aquaria stocked with 10 fish and maintained for 45 days. Treatment means were evaluated by one-way analysis of variance and Duncan's multiple range test. The 15 and 20 mg/L treatments produced higher lightness and lower redness and yellowness than the control and 5 mg/L treatments. At 20 mg/L, survival declined to 66.67 ± 15.28% and the condition factor declined to 0.96 ± 0.13. These results show a marked fading of red and yellow body-colour components at 15 to 20 mg/L, while reduced survival and condition factor were most evident at 20 mg/L. Digital CIE L*a*b* metrics may therefore provide a practical visual endpoint for screening sublethal responses of ornamental fish to nominal PVC microplastic exposure. The study did not test the physiological mechanisms that generated the colour response.
Copyrights © 2026