||Growth performance, digestive and metabolic activities, and contents of peripheral hormones of spotted sea bass (Lateolabrax maculatus) juveniles were evaluated under natural light and three different light spectrums (white, blue and red) in combination with three photoperiods (light: dark cycle, 12: 12-h, 18: 6-h and 24: 0-h). Bass in 18-h blue light environment displayed the best growth performance and digestive enzyme activities, while red light environment significantly impeded growth and digestive enzyme activities. Altered contents of melatonin, cortisol, thyroid hormones (T3 and T4), and testosterone (T) were observed in bass reared in red light, suggesting that red light could disturb endocrine homeostasis associated with biological rhythm (melatonin), stress coping (melatonin and cortisol), growth and development (T3 and T4), and aggressive behavior or hyperactivity (T3, T4 and T). Impaired growth performance might be due to energy used to cope with stress. We concluded that the red spectrum environment was stressful to spotted bass and the selection of appropriate light conditions (such as 18-h blue light) might lead to a beneficial outcome for spotted sea bass culture.