Neverwinter: The Year of Deep Water Drifting
Something corrupted the fish of the Neverwinter River with fiery magic from the Elemental Chaos. As a result, swarms of hetfish – essentially fiery piranha – are becoming more and more common (cf, 1E’s WG5 Mordenkainen’s Fantastic Adventure and its 3.5E conversion in Dungeon 112). Some even reach the city of Neverwinter.
Electric eels are also common and many of the smaller tributaries often have their flow reduced because of enormous dams built by giant beavers.
What fills many who use the river with fear are the tails of an enormous catfish-like creature, the verme, reportedly large enough to swallow a troll or a hill giant whole.