The indigenous technologically advanced societies can be divided between the Land dwelling and the Aquatics. Aquatics have only very recently begun to emerge from the water, in the form of genetically modified versions of the origional stock.
The majority of the native cyantians do not have mammary glands - most of the infants can eat immediately after birth. The Neefla handle it pretty much like Dolphins do, they do have a kind of mammary gland.
They also have their own languages which differ than that spoken by the Immigrant Cyantians.
All oceanic species live much longer life spans, in addition, the posses a genetic memory that gets passed from one generation to the next.
The genetically enhanced Craihs, Raiey and Neefla can sleep either normally or in the water. The first two have an easier time at it since they can breathe without moving. Neefla, still need to surface for air and the only purpose for sleeping in water would be for their skin. It is not necessary for them to sleep in the water, but it's more comfortable for them. Might take into account that they're also a good deal heavier than your average cyantian or human of similar height. Neefla tend to be pudgy.
All three of these aquatic species do need periodic immersion to keep their skin from drying out.