The Quarren were squid-like with four facial tentacles which protruded from their lower jaw. They had a pair of deep, turquoise eyes and finned hands with suction-tipped fingers. As an amphibious species, they were strong swimmers and could also squirt clouds of ink as a defensive measure. They were also bipedal beings that could walk and sit upright.
During the Clone Wars, the Separatists, acting through the Karkarodon advisor Riff Tamson, stirred up trouble between the Quarren and the Mon Calamari. Following the assassination of the Mon Calamari King Yos Kolina, the Quarren led by Chieftain Nossor Ri contested his son Prince Lee-Char's claim to the throne. With the encouragement of Tamson, Ri called for new leadership and a chance for Quarren to rule Mon Cala. This led to a civil war on Mon Cala with the Separatists backing the Quarren Isolation League and the Republic supporting the Mon Calamari. Prior to the outbreak of fighting, Senator Padmé Amidala and her Jedi bodyguard Anakin Skywalker visited Mon Cala city in attempt to broker peace between the two warring species.