At one point in my webcomic, I was going to have Riki need to go underwater for some reason. He might have been born in a desert, but he did learn to swim. But he still needs SCUBA equipment to do serious underwater exploration.Phillee doesn't need anything unless she's dealing with harsh conditions or extended time underwater (she can't support herself on gills alone indefinitely if she wants to stay conscious, but they and a deep breath can last her for a couple hours of hard work). That and decompression sickness isn't nearly as much of an issue for her and she is medically competent and a far better swimmer than any of the other crew, so she's a good spotter. And she doesn't have to waste air talking* when she has telepathy. So I like the contrast between Phillee in her birthday suit and Riki in full SCUBA gear underwater. (You can also tell that, despite the ponytail, she really is non-mammalian, which is why this doesn't get a content label.) * Phillee's voicebox still requires some air to pass over it to make sound, even if she's not breathing.