In August 2025, anglers off Costa Rica’s Caribbean coast got the shock of their lives. Expecting a typical grey nurse shark, they were instead greeted by a nearly two-meter-long shark glowing in bright orange with striking white eyes. Scientists later confirmed this rare phenomenon is due to xanthism, a condition causing excess yellow or golden pigments, combined with albinism in its eyes, creating a dual anomaly known as albino‑xanthochromism.

Normally, nurse sharks rely on muted colors to camouflage on the seabed and avoid predators. But this vibrant shark, despite its conspicuous appearance, survived into adulthood without harm, defying conventional survival assumptions. Researchers suggest that factors like inbreeding, environmental stress, elevated temperatures, and hormonal imbalances may also influence such unusual pigmentation.

This discovery is the first documented case of xanthism in a free-swimming nurse shark in the Caribbean, highlighting the genetic diversity of marine life and raising awareness about conservation. While common in some regions, nurse sharks face threats from fishing and habitat degradation, making each rare sighting a reminder of the fragile balance in our oceans.