Whereas the Mon Calamari race chooses to live near the surface, the Quarren are more accustomed to deep-sea living, and choose to live below the water. Their conservative and solitary nature make them unwilling to trust new ideas or lofty concepts. When they first came in contact with the shore-dwelling Mon Calamari who shared their homeworld, 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 Dac'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. Tensions flared during the Clone Wars, when the Mon Calamari remained loyal to the Galactic Republic while the Quarren sided with the Separatists. A temporary truce that was forged in the wake of the Clone Wars was dashed when the Empire subjugated the planet Mon Calamari. The Quarren chose to remain passive, leaving the battle to the Mon Calamari, whom many Quarren believed had brought the Empire to their homeworld in the first place.
However, the Quarren could not escape the Empire, and it was rumored that a Quarren helped the Empire evade the Calamarian defenses 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 defenses 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 neighbors the Mon Cal did.