Summary: Maia & Volpato (2013)

The colour of environmental light can influence the stress-induced cortisol response observed in fish. Maia & Volpato (2013) investigated the effects of three (blue, yellow, white) environmental light colours on the stress response (changes in ventilatory frequency) of Nile tilapia Oreochromis niloticus to confinement. They found that, after 7 days, fish ventilatory frequency was similar under each environmental colour. Similarly, after a 15 minute period of confinement, ventilatory frequency increased, regardless of environmental colour, in the first period (0-4 minutes). Interestingly, Maia & Volpato (2013) found that, irrespective of time, fish kept under white light showed a higher post-confinement ventilatory frequency compared to fish kept under blue light. They suggest that Nile tilapia should be maintained under blue light to minimize stress.