The Congo River is an ecosystem built on pressure and motion. Tetraodon miurus isn’t merely surviving there: it’s engineered for it. Its flattened body, dense musculature, and anchored posture aren’t quirks of behaviour, but solutions to physics. To keep one is to study a living example of how evolution solves chaos with precision.

The Mbu Puffer (Tetraodon mbu) is the undisputed giant of the freshwater pufferfish world. It is native to Central Africa, with a distribution spanning much of the Congo River Basin, including the wide expanse of Pool Malebo (Kinshasa–Brazzaville) and extending into Lake Tanganyika.

Many species of freshwater, brackish and marine pufferfish bury themselves into the substrate. This behaviour is known as "wallowing" and...