A tiny, noodle-sized fish in the Congo defies gravity to scale sheer waterfall cliffs. When Alex Honnold free-climbed a 101-story skyscraper in Taipei, the world cheered. But deep in the upper Congo River Basin, an overlooked fish the size of a macaroni noodle regularly scales its own proportional skyscraper: a roaring, 50-foot wall of... [6902 chars]