They might look like cartoon characters, but owning one is more like babysitting a venomous toddler with food issues.

Puffer fish are the ultimate bait-and-switch. Big eyes, tiny fins, round bodies—they look like underwater plushies. But behind that Pixar exterior is a fish that can kill you, ruin your tank, and self-destruct out of sheer stress. People think they’re getting a quirky addition to their aquarium, but what they’re actually signing up for is a high-maintenance hazard with attitude problems. Here’s why that adorable puffball is a disaster pet in disguise.