I am using Keveranu as a basis for the general idea of what a Xiahwenite of Keveranu's bloodline looks like when in water. Keep in mind that this is a form they can take at will. It is not an involuntary thing. One thing I failed to note in my concept art was the tail. So the Bimahojah swim with their legs and tail in synch with one another. This allows for very fast swimming speeds of up to 15mph. They swim with a dolphin style swimming method.

For those that cannot read my writing:

Arrow pointing at ears: Tuft filled with electroreceptors. (This gives him the ability to detect other things in the water via electric impulses. Like a shark.)

Arrow pointing at neck: A mixture of gills and lungs allow for breathing water and air.

Arrow pointing at dorsal fin and webbed feet and hands: Webbed hands and feet and dorsal fin allow for faster and agile swimming. (The dorsal fin allows for stability.)