Species originating from Bolarus IX. They are a humanoid Federation species that mingles well with humans, even though they are relatively rare in Star Fleet. Having evolved from an aquatic race they are semi-amphibious and are still very at home in the water, although mainly based on land. They are easily distinguished by their peculiar blue skin that ranges from a yellowish green tinge to a blue darker green tinge, to medium and deep blue. This is from their blood, which is also blue, and chemically incompatible with most other humanoid races, save for Andorians.

The Bolian tongue has a cartilaginous lining and their digestive system greatly differs, making them capable of eating foods that would make 'normal' species' sick or dead.

A narrow yet characteristic ridgeline runs from over the skull from the spine to the nose and down the neck and continuing down, essentially splitting them in half. Bolian religion has it that the ridges come from the god piecing together the sky and the ocean, creating the living being out of these two halves. In addition, they have longer ears than humans, and are by nature bald once they reach adulthood.

As a culture, the Bolians place a high importance on observing details, making them excellent in careers where high accuracy and meticulousness are required. They are very open, easy-going and extremely chatty, sometimes to the point where humans find them intrusive. To a Bolian, rudeness and sadness are traits that need correcting, preferably immediately, and they will happily give advice, asked for or not. If said advice is rejected, they will, being the meticulous beings they are, attempt to learn everything about the subject to be able to give better advice next time. Their marriages sometimes include three (or more) partners.

In addition, they are way cool. Just ask Droj.

Sources: Startrek.com database, various episodes (TNG, DS9 & Voy). Text in italic is speculation.