They look like they are made completely made of water, look humanoid. They are solid, however, just translucent.
The Aqiuals were always a mentally advanced species. They were at the intelligence of modern man by the year 800 A.D. and only continued to progress after that. As they did so their minds developed to develop Psi powers such as mind reading, mind speaking, and others. There is legend and myth that said the species was able to control water a long time ago, but none know if this is true. The mists of antiquity took all evidence of the truth of this myth away.
Be that as it may, the Aqiuals think that there must have been some water control. There is good reason for this. Their bodies seem to be completely made of water. This effect is complete with being able to see through them, and their skin rippling from touch. But unlike water they are very solid; Your hand would stop once touching the surface. So in essence they are true beings. No organs can be seen, but they must be there.
The planet Techigora is like Ancient Terra was, mostly water. The Aqiuals lived on land, which is something none would expect. Not many of the species have left this planet as they want peace and harmony of the unspoiled planet. A few adventurous ones struck out with different explorers that "discovered" the planet and found themselves in the rest of the Universe, including USI.