Physiology and Culture Edit
The Xindi-Aquatics had evolved to living underwater. Their underwater vision was far more advanced compared to humanoids. They had three fingers in each forelimb, ending in short fingernail-like claws. Like all the Xindi species, they had that distinctive ridge on their cheek bones. Aquatic females were larger than males, and had a rougher skin and a more humanoid-looking face than the Aquatic males.
The Aquatics were known to be very enigmatic. Their species was also known to take decisions very seriously, over-analyzing every situation they faced. In one occasion the Aquatics took six days only to decide to attend a meeting with the Council. (ENT episode: "Countdown")
Aquatic language was the most difficult and complex of all the Xindi. Because of their underwater lives, they didn't use their mouths to communicate. Instead of it they used some kind of sonar. However, they could easily learn several humanoid languages in order to communicate with them, a considerably easy task compared to their advanced communication system. (ENT episodes: "Countdown", "The Council")