Light is just one aspect of an animals environment. Many factors influence why an animal will live in one environment over another. Availability of food, safety from predators, space to live and reproduce, and the list goes on and on. We can't pic one aspect of an animals natural environment and assume that this is why they live where they do, or that it is needed for the animal to live a long healthy life in captivity. If people are keeping this animal in brightly lit aquariums, and they seem active and healthy, it suggests that light is not a crucial aspect of the animals well being. Every time we take an animal from the wild, and keep it in captivity, we change many aspects of its environment. Despite this fact, many animals in captivity live longer, grow larger, and become more physically fit, than their relatives in the wild.