Most recent freshwater fish extinction

The most recent fish extinction is that of the Chinese paddlefish (Psephurus gladius), one of only two species of modern-day paddlefish (the other is native to North America). One of the largest species recorded from fresh water, it grew to a confirmed maximum length of 3 metres (9 feet 10 inches) and weighed up to 300 kilograms (660 pounds) – although much larger, unconfirmed specimens have been reported, one as long as 7 metres (23 feet) and weighing 450 kilograms (990 pounds). The species was characterized by its very lengthy paddle-like trunk, vaguely resembling that of an elephant. It had been categorized as Critically Endangered for a number of years, and had not been seen since 2003 in either the Yangtze River basin or the latter river's East China Sea estuary that constituted its only known habitat in recent times (historically it was also known from the Yellow River). Accordingly, in January 2020 this species was formally announced to be extinct by the Chinese Academy of Fishery Sciences and the International Union for Conservation of Nature (IUCN), who consider that it likely died out sometime between 2005 and 2010, owing to overfishing and habitat loss.

Belonging to a taxonomic family of fishes related to the sturgeons, the two modern-day species of paddlefish are popularly referred to as being primitive or even as "living fossils", because their overall morphology is little-changed from that of fossil relatives that existed over 70 million years ago during the late Cretaceous Period.

Although spending much of its life in fresh water, Chinese paddlefish were technically anadromous – that is, at different stages of their life they live in fresh water and salt or brackish water, migrating inland from estuaries and basins in order to spawn. However, like many aspects of their behaviour, their depleted numbers meant that very little detail was known about their migratory habits.

Other than the Chinese paddlefish, the only known modern-day representative is the somewhat smaller American paddlefish (Polyodon spathula). It is native to the Mississippi basin in the USA, but has also been farmed on a large scale and therefore is presently not in any imminent danger of extinction, although it is categorized as Vulnerable by the IUCN due to fishing pressures and competition from invasive species within its historical range.