Blowfish

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

History
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) Emily Holroyd also referred to Blowfish as Homoformatus piscis. (TWN: Consequences: The Baby Farmers) 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 102 AD, a Blowfish was part of the Alliance and was present when the Doctor was placed inside the Pandorica. (DW: The Pandorica Opens)

In 1899, 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 by Torchwood agent Alice Guppy, which Harkness objected to. (TW: Fragments)

In 2009, 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)