Ockoran The Ockorans were an aquatic species . Biology . Ockorans looked partly humanoid , with a humanoid upper half and a fish - like tail . They had bright pink skin , black eyes , thin mouths , no noses and white wavy crests instead of hair . Their upper body was lightly built , with thin arms with three webbed fingers . Despite their weak appearance , Ockorans were dangerous fighters and much stronger than they looked . Their lower half was like a fish , with a scaly tail and fins . Ockorans had three gills down the side of their body and were unable to survive out of the water , suffocating in minutes . Male Ockorans could be identified by their lighter coloured crests , as well as differently shaped gills . Ockorans had a long lifespan , over hundreds of years . Ockorans had violet - coloured blood . Oddly enough , the Ockorans had a slight genetic resemblance to the dolphin s of Earth , as well as to the Kalarian s of Kalaya . ( PROSE : " The Final Sanction " ) Technology . The Ockorans were known for their advanced technology and the Sixth Doctor believed that their weaponry was " phenomenal " . ( PROSE : " Killing Ground " ) The Ockorans were one of the few aquatic races who evolved to have Level Two technology . ( PROSE : " The Murder Game " ) After their wars with the Kalarians , the Ockorans started developing technology and taking it from other species . Ockorans commonly used organic technology . ( PROSE : " The Final Sanction " ) They had thinker - weapons comparable to the organic ships of the Zygon s and the Faction Paradox ' s shrine . ( PROSE : " Alien Bodies " ) Ockoran ships were black , tube - like structures with three anti - gravity disc s on the underside . Ockoran ship were flooded and the engines would only work underwater . ( PROSE : " Killing Ground " ) The most recognisable technology used by the Ockorans was the Selachian battlesuit s . These battlesuits were large , bulky things that gave the Ockorans the appearance of humanoid s . Ockorans had to have studs implanted into their nervous system and have their tails removed in order for them to use the battlesuits . They had plasma weapons attached to their arms , which were built for fear rather than power ( though it was still a dangerous weapon ) . Their helmets were shaped and painted to look like shark s in order to intimidate their enemies . Later battlesuits were equipped with nanite s to repair damage and to counteract the nanites of the Terran Security Forces . Ockoran transports looked like armadillos with tank - treads . They were organically based and responded to telepathic commands from Ockorans . They could spit nerve gas and , when the Terran Security Forces counteracted that , acid . Ockorans also had a wide variety of technology that was used during the war with the Terran Security Forces . They used special spores underwater that would burn when exposed to air . Ockoran also used the Cloak , which could blind and capture enemies . They left organic weapons on Kalaya that would activate once they left and would attack the nervous systems of any surviving humans . Ockorans made a tough rope out of kelp . ( PROSE : " The Final Sanction " ) They also used thermosystron bomb s . ( PROSE : " Alien Bodies " ) Culture . Ockorans lived in cities carved out of the rocks at the bottom of the sea . There were openings all around the buildings for the Ockorans to swim into . Ockoran ' s language was made up of singing and though it was hard to translate , it was considered to be very melodic . The Ockorans believed in a being called the Great Mother , a being who was the mother to the Ockorans and who guided them through the world . They also believed that the land ( called the Second World ) was where the wicked souls went and the inhabitant of the land were jealous of the Ockorans . Legends state that the Great Mother was killed trying to protect the Ockorans from the Kalarians , which led to an intense hatred of all air - breathers . ( PROSE : " The Final Sanction " ) History . At some point before the 22nd century the Ockoran ' s home - planet of Ockora was discovered by the Kalarian s and chosen as a vacation spot . Though the Kalarians knew of the Ockorans , they believed they weren ' t intelligent and hunted them for sport . ( PROSE : " The Final Sanction " ) Likewise , Arix set up cruise ships for people who wanted to hunt them . The Eleventh Doctor was able to stop her and bring her to Galactic Security . ( COMIC : " Peril on the Sea " ) Eventually the loss of the Ockorans were too great and they developed their battlesuits to fight back . ( PROSE : " The Final Sanction " ) They emerged from the oceans during a culling festival and took their revenge on the Kalarians . Their homeworld was cordoned off and the Ockorans were eventually forgotten . ( PROSE : " The Murder Game " ) In order to take revenge on the air - breathers , the Ockorans set out into space following the Kalarians . They conquered Kalaya within 6 months and took 3 more planet s within a year . They soon spread out , conquering more planet , trading with other species and forming the Selachian Empire . They soon became a major power on the galactic markets . ( PROSE : " The Final Sanction " ) By 2069 , the Selachians had encountered human s . They were featured in the " Eye - Spy Book of Alien Monsters " , which was handed out to UNISYC personnel as potential threats . ( PROSE : " Alien Bodies " ) The Selachians conquered Rho Priapus , but they were driven off by the Space Marine s . ( PROSE : " The Janus Conjunction " ) In 2136 , the Selachians attacked Hotel Galaxian . They were defeated by the Second Doctor , Ben Jackson and Polly Wright . ( PROSE : " The Murder Game " ) In 2191 , the Cybermen had stolen a Selachian ship . ( PROSE : " Killing Ground " ) For decades , the Selachians and the humans had traded with each other . Eventually , towards the end of the 22nd century , one deal went particularly bad , causing the humans to declare war on the Selachians . The war went badly for the Selachians and by 2204 they had been pushed back to Ockora . Though they had taken prisoners on planets they were forced to leave , such as Molinar and Kalaya , this wasn ' t enough to save them and Ockora was destroyed by General Wayne Redfern when he dropped the G - bomb . After the meddling of the Second Doctor , the Supreme Leader and 40 Selachian soldiers were able to escape the planet ' s destruction and get on - board the " Triumph " . They killed everyone on the ship , but the other G - bomb was accidentally set off , leading to the formation of another black hole . ( PROSE : " The Final Sanction " ) Other references . Samantha Jones wondered if the Ockorans had the technology to melt stone . ( PROSE : " Revolution Man " ) In an alternate universe , the Selachians attacked Moonbase in 2044 . ( AUDIO : " The Architects of History " ) Jack Harkness told a story about when he met the Selachians . ( PROSE : " The Stealers of Dreams " )