Tilapias are among the most important warm-water fishes used for aquaculture production. One of the species gaining popularity nowadays is the red tilapia due to its appealing colour and taste. In this study, six red tilapia were exposed to the blue or red light-emitting diode (LED) and three to natural light (control) and changes in eye colour pattern (ECP), ventilation rate (VR) and body colour of the fish were observed. Each light condition was kept for 8 hours, from 800 h to 1600 h for 15 days. Results showed that significantly darker ECP, faster VR and intensified red skin colour were observed in treatments exposed to blue and red LED compared to those in the control treatment (natural light). Based on the results of the study it can be noted that exposure to blue and red LED causes stress in fish but it is not lethal since no mortality was recorded.