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, he stole a sports car and was tracked down by Torchwood, he took hostages in order to bargin for his release, unlucky for him Jack Harkness had a good shot a calmly used this skill to kill the blowfish with one bullet. (TW: Kiss Kiss, Bang Bang)