Salarians

Salarians are giant fish that, for some reason, move, think and talk really really fast. They annoy everyone with their ridiculously fast talking, so the only organizations that would accept them as members are the Tri-Council (consisting of Turians, Salarians and Asari) and the League. The Salarians have a very short lifespan, only reaching the age of about 40 years before dying of old age. Extending the age of a Salarian is difficult, their hyperactive metabolism makes it exponentially more difficult to preserve their lifespan when compared with a Human.

Salarians are native to the planet Sur'Kesh, which coincidentally shares its name with a popular Mon Calamarian meal, the Sur'Kesh Salmon, made from only the finest 100% pure fish (possibly amphibian) flesh. Salarians are warm blooded, yet still amphibians, which means their entire biology is messed up and so weird that Salarians were one of the first targets for the Reapers during the Reaper war.

Their species magically went extinct in the year 500,000,000 due to an increase in Mon Calamarian Sur'Kesh dishes. No-one ever got to the bottom of that actually...