Would a cetacean need brightly lit quarters? Their natural environment deep in an ocean is generally a lot darker.
deep ocean creatures are adapted to a lack of sunlight, they're also not eligible to be crew members, since they're not intelligent. Who knows what cetacean lifeforms from other worlds would require.
Physics is physics, thought. Light will only penetrate so deeply into a liquid body.
Now, alien cetacean creatures may live more in the shallow end of the ocean, who knows. But, then, would they fit the definition of cetacean as opposed to amphibian?