The bipedal, amphibious species known as the Mon Calamari come from the planet of the same name. The Mon Calamari are shore-dwellers with an affinity for water. They developed a symbiotic relationship with the water-dwelling Quarren who also inhabit their world, and this joining led to the planet's golden age.
With the Quarren to mine ore from the ocean floor and the Mon Calamari to design practical uses for the metal, the great floating cities of Mon Calamari were built. These cities extend above and below the water, and the technology was eventually used to create orbiting space platforms.
The Mon Calamari see space as an endless ocean of stars, and they were tempted to explore those depths from the earliest periods of their civilization. First they colonized their own star system, then they discovered the secret of the hyperdrive. But before they could reach out to find the galactic community they dreamed of, they met the Empire.
The Empire did not want to share anything with the Calamarians. They wanted to use the gentle folk and their technology to further their own war effort. When the Mon Calamarians refused to become slaves, the Empire destroyed a number of floating cities.
It was the Empire's opinion that such a display of destruction would cow the peaceful people. Instead, they learned to fight back, their star cruisers becoming among the best capital class fighting ships in the galaxy. After repelling the Imperial forces, the Mon Calamarians discovered the Rebel Alliance. They joined with this group, pledging to fight for the dream of freedom until the Empire was finally destroyed.
Mon Calamari characters readily demonstrate their scientific heritage with advanced skills in surgery and repair.