From Holocron - Star Wars Combine
|Language||Quarren language |
|Average Height||1.7 to 1.8 meters |
|Skin color||Varies during mating |
|Distinctions||Mouth tentacles |
|Average lifespan||79 years |
|Known Members||List of known Quarren|
The Quarren are a humanoid race native to Calamari's deep oceans. They have helmet-shaped heads that are composed of a mass of tentacles set below close-set eyes. They are more accustomed to deep-sea living, and chose to live below the water. Their conservative and solitary nature has led them to be unwilling to trust new ideas or lofty concepts.
When they first came in contact with the shore-dwelling Mon Calamari, the Quarren were hesitant. They eventually began to cooperate with the Mon Cal, and together they developed a symbiotic relationship in which the Quarren provide the raw materials, and the Mon Cal provide the knowledge and expertise; this led to the construction of the huge floating cities that dominate Calamari's oceans. Because of their pragmatic nature, the Quarren did not want to travel and explore the stars, as the Mon Cal did, and this began to create friction between the two races. When the Mon Cal's dream of contact with other stars became the deadly war with the Empire, the Quarren chose to ignore it, leaving the battle to the Mon Calamari who brought it upon themselves.
However, the Quarren could not escape the Empire, and it is rumoured that a Quarren helped the Empire evade the Calamarian defences and overtake the planet. Unfortunately, the Quarren were enslaved along with the Mon Cal. When the Mon Cal resisted Imperial rule, the Empire began destroying the floating cities. This served to unite the two races temporarily, and together they were able to solidify their defences and drive off the Empire with nothing more than crude weapons. After that, there were a number of Quarren who left the planet, seeking a life among the stars as their neighbours the Mon Cal did.
Biology and appearance
Quarren were aquatic humanoids with squid-like heads, at least four tentacles on their faces, and leathery skin. Quarren tentacles were prehensile, and they were able to manipulate food with them. Quarren had small mouths, with two fang-like teeth jutting from their faces on either side, and a long, thin tongue sticking out in between. Quarren had two long protrusions that extended from either side of their faces. In these protrusions were several gill-like structures that were actually aural structures, used for hearing instead of ears. Quarren also had holes on either sides of their neck that were most likely used for breathing. Quarren had two sac-like organs that hung from the back of their heads as well. 
Most Quarren had orange skin, although some Quarren had gray-green skin - this trait, however, was extremely rare. Pink or purple-skinned Quarren existed, though presumably in small numbers. All Quarren also had two shimmering blue eyes. Being aquatic in nature, Quarren had to keep their skin moist in order to stay alive, although clawed Quarren seemed to need less moisture than other Quarren.
There were three different types of Quarren, although the only difference lay in their hands. Some Quarren had suction-tipped fingers, either with three or five fingers. Other Quarren had thick fingers that lacked suction cups on the tips of their fingers, yet had sharp claws instead. Whether these three groups were actually distinct subspecies is unknown. 
Having evolved in the depths of Mon Calamari, Quarren could descend to depths of 300 meters without any breathing or pressure apparatus. However, when descending to 50 meters or deeper, they had to spend as much time decompressing as they spent under 50 meters of water to allow their bodies to readjust to the lower surface pressure.
Society and culture
Quarren were a very self-centered and proud species, almost to the point of being xenophobic, which would coincide with their isolationist behavior. Quarren found Humans to be very crude beings and thought their language (Galactic Basic) to be very cumbersome, and unsuitable for speech. The Quarren instead spoke their native language more frequently, in contrast to the Mon Calamari who spoke Basic far more often, in order to deal with off-worlders, which the Quarren seldom did.
In sharp contrast to the Mon Calamari, the Quarren were far more conservative and practical in their thinking. While the Mon Calamari looked towards the future, the Quarren remembered yesterdays. Also, while the Mon Calamari often traveled throughout the galaxy, the Quarren were far more isolationist, staying, for the most part, in the depths of the oceans of their homeworld. However, some Quarren followed suit after the Mon Calamari, and made their living in the galaxy as business managers and accountants.
While the Mon Calamari manufactured starships in orbital shipyards, the Quarren diligently mined metal ore for their brethren from the deepest parts of the ocean. The Quarren also helped build massive floating cities for the Mon Calamari. While most Mon Calamari lived on the few scattered islands on Dac, or on the upper levels of their floating cities, the Quarren lived in their own cities, deep beneath the waves, or in the lower levels of the cities, for the cities stretched far below the surface, and the Quarren loved the dark far more than did the Mon Calamari.
The Quarren species evolved in the low-pressure depths of Dac's oceans. Here they mined the mineral-rich sea floor. They shared the depths of the planet's ocean with the Whaladons, the Moappa, and the Knowledge Bank. Circa 4,500 BBY the Quarren met the Mon Calamari, who lived in the shallow parts of the ocean, for the first time. However, rather than meeting in friendship, the Quarren were suspicious of the Mon Calamari and attacked them. This instigated a long war between the Quarren and the Mon Calamari. However, the Mon Calamari, though less aggressive by nature, had a superior level of technology, and won the war. The Mon Calamari, however, did not want to risk further wars, which they thought would only lead to the extinction of the Quarren.
While the Quarren recovered from the previous war, the Mon Calamari prepared for a daring cultural experiment. In order to prevent future wars, the Mon Calamari took hundreds of young Quarren captive, and taught them the ways of Mon Calamari civilization, teaching them the arts, sciences, and ethics. Once they had fully educated the Quarren, the Mon Calamari released them back to their homes. The elder generations of the Quarren distrusted the younger Quarren, and viewed them as brain-washed usurpers. The Quarren youth, on the other hand, viewed their elders as uneducated barbarians. However, the youth eventually grew up and assumed control of Quarren society, and peace between the Quarren and the Mon Calamari continued for centuries (though it was sometimes a tense relationship as followup generations of Quarren slowly began to sink back into their traditional values).
The planet was contacted by the Galactic Republic circa 4,000 BBY.
Soon, many Quarren headed off-planet and became business managers and accountants. During these years Quarren went as far as Taris, Telos IV, and Nar Shaddaa. Several Quarren joined the Exchange, managing the criminal syndicate with efficiency. 
Later, Mon Calamari joined the Galactic Republic and eventually gained representation in the Senate. During at least the last decades of the Galactic Republic, the government of Mon Calamari, and its representation in the Galactic Senate, was shared between the Mon Calamari and the Quarren. 
References:  - http://starwars.wikia.com/wiki/Quarren