Jellyfish populations are surging worldwide, largely due to human-driven environmental changes. Overfishing removes the predators that naturally keep jellyfish in check, while warming oceans from climate change expand jellyfish habitats. Excess nutrient runoff and pollution create low-oxygen “dead zones” where jellyfish, more tolerant than fish, can thrive. These blooms may clog fishing nets, disrupt power plants, harm tourism by causing beach closures, and threaten marine biodiversity. Instead of targeting jellyfish themselves, experts emphasize addressing root causes: restoring predator populations through sustainable fishing, reducing pollution and nutrient runoff, and mitigating climate change. Only by rebalancing marine ecosystems can we prevent oceans increasingly dominated by jellyfish populations.