Aquatic fish people who need water to breathe; Zev is one, and notably thinner than the rest.
Carl sees a kua-tin out of her suit for the first time when Zev turns up physically in the Production Trailer wearing only a simple rebreather at her throat rather than her usual diving apparatus. What strikes him is not the novelty but the comparison: she is strikingly thin next to every other kua-tin he has seen.
The species' dependence on moisture is on display throughout — the rebreather mists constantly, soaking the couch she sits on until she pulls herself off it and onto the floor. Small enough for a cat to greet head to head, she is described as a small fish woman.
Small fish-like humanoids, wide-mouthed and slick-skinned, normally bulky-bodied, requiring a diving suit or a throat rebreather that vents a constant soaking mist to survive in dry air.
Zev's species, and the yardstick by which Carl registers that something may be wrong with her.
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