Blowfish

Blowfish was a name given to an unknown race of piscene humanoids with a face strongly resembling a blowfish.

Toshiko Sato described them as some sort of "landfish" and her scan of one member of the species revealed high levels of algae. (TW: Kiss Kiss, Bang Bang) They seemed to have a weakness to Human pleasures and on Earth committed a wide variety of crimes. (TW: Kiss Kiss, Bang Bang, Fragments)

In the 19th century, Jack Harkness was sent to collect a young Blowfish by Torchwood 3. He was brought back to the Hub, but since there was no way to return him, he was simply shot dead. (TW: Fragments) Later, in the 21st century, another Blowfish was in league with the Time Agent Captain John Hart.

He also fell victim to temptation, stealing a sports car and embarking on a drug-fueled joyride through Cardiff. He was tracked down by Torchwood 3. He took hostages in order to bargain for his release, but Jack Harkness was a good shot and calmly used this skill to kill the blowfish with one bullet. (TW: Kiss Kiss, Bang Bang)