the sword sturgeon
(Psephurus gladius)
you were big, had an extravagant appearance, and belonged to the probably most unique creatures on our planet. However, they have never received enough publicity or protection efforts, and unfairly so. Up until the 1970s, huge quantities of the bizarre, up to 500kg heavy and allegedly 7m (even if rather a little over 3m) long were still being made Sturgeon fished. But after the construction of a dam in the Yangtze River, the increasing shipping traffic and the enormous pollution of the almost 6400km long river, the stocks collapsed within a very short time. And even in 1985, 32 individuals of the sword sturgeon could still be caught. In 1995 even juveniles of the species could be detected, but on January 24, 2003 the last sighting of this unique species took place. Since then, the fish has long been regarded as an acutely endangered species, but even intensive search efforts have not been able to detect a sword sturgeon since then. So he became in January 2020 for Declared extinct after not having seen a single specimen since 2003.