Phenotypic variation and relationships in body weight and composition traits of domesticated snakeskin gourami (Trichopodus pectoralis) at harvest

Phenotypic variation in organisms arises from diverse sources, each with unique implications for adaptability to selection and environmental changes. This variation is particularly significant in tropical aquaculture, exemplified by the snakeskin gourami ( Trichopodus pectoralis ), a popular whole-body sale fish. Understanding these variations is crucial for optimizing animal breeding and commercialization efforts. This study explores previously uncharted territory by investigating the relationships among body weight (BW), total length (TL), body depth (BD), and Fulton’s condition factor (K) using 8,345 records of domesticated snakeskin gourami fish at the 9-month harvest point. Interrelationships between these traits and the associations between BW and other characteristics were examined and compared for each sex. Sexual dimorphism was evident, with females being significantly more extensive, and it showed higher variation and a stronger correlation between traits than males in all characteristics. The population was categorized into six market sizes (XL, L, M, S, XS, and XXS), with XXS being the most abundant (36.35%), followed by XS, S, M, L, and XL (31.95%, 23.30%, 8.06%, 0.31%, and 0.04%, respectively). There was mostly a male population in the XS and XXS size categories compared to a female population. Strongly significant correlations emerged ( p  < 0.0001), with BW highly associated with TL and BD and moderately associated with K. This study underscores the importance of understanding sexual dimorphism and trait correlations in domesticated snakeskin gourami for informing selective breeding and commercial strategies in tropical aquaculture.