African catfish

YouTube

During heavy rains last year in a small town outside Havana, people saw something remarkable. Large freshwater catfish called claria were swimming in the flooded streets. In a video posted on YouTube, excited locals splash out to grab them.

But that happy scene was also an environmental alert. Claria are an invasive species in Cuba. They’re supposed to be confined to aquaculture fisheries, where they’re bred for food. Outside those farms – as these claria obviously were – they’re notorious for devouring anything in their paths.