Andoan mineral - fish Andoan mineral - fish were a swimming crustacean species native to Ando . Biology . The mineral - fish fed off of ore veins in deep undersea caves . After taking the nutrients it needed for energy , it used leftover metals to create a thick exoskeleton with an armored carapace and a snapping beak . The mineral - rich shells were harder than plasteel and resistant to energy weapons , and were highly valuable as a result : a single meter - long organism could be worth ten thousand credits . The mineral - fish industry was a major component of the Andoan economy . Andoan mineral - fish were normally about half a meter long and were covered by a thick shell . They had a sharp spiked tail which was used to break up large rocks , but could also be deadly when used to defend against predators . They also had a number of shelled fins used for propulsion and to break rocks down into edible chunks ; while seldom used in combat , the fins were rough and abrasive and could cause serious injury to anyone who brushed them . Because of their fins and incredible strength , Aqualish harvesting mineral - fish waited several hours for the fish to " suffocate " in the air before daring to extract the minerals from the fish . The fish had a lifespan of three to five years , reaching full maturity after about one and a half years . Adult females could lay eggs about once every five months , producing hundreds of small , hard - shelled eggs which appeared similar to ball bearings . Females built nests in calm , shallow pools near the coasts , as fewer natural predators prowled those waters . History . Andoan mineral - fish were once plentiful in the rich seas of their world , but they became a prime commodity in the wars between the two Aqualish races and their populations dwindled . Only after the Galactic Republic became guardian of Ando did the population return to pre - war levels . After the collapse of the Republic , the Galactic Empire once again began harvesting the animals . The Aqualish used mineral - fish as a cheap means of harvesting metals vital to their war efforts . As the Empire and the Rebellion competed for resources , the rare alloys they produced were critically important to the war effort . One of the alloys found in their shells was purified sedrellium , an expensive high - strength alloy used to reinforce the hull of the Incom Corporation ' s X - wing fighter . Great fishing platforms prowled the seas of Ando looking for mineral - fish schools to harvest . The shallow waters containing mineral - fish nests were patrolled by Imperial skiffs to prevent Aqualish from harvesting immature mineral - fish , but the Empire allowed unlimited harvesting of mature mineral - fish . Experiments with controlled breeding of Andoan mineral - fish were a complete failure : Andoan mineral - fish placed in controlled environments did not survive more than two to three standard months and there were no recorded cases of eggs hatching while in captivity . There was also extensive research into their bio - chemical processing ability , but scientists were not been able to artificially duplicate it . A number of mining firms invested in this research in the hopes that a cost - effective artificial filtering process could be discovered .