Pale Catfish

Rhamdia guatemalensis

The pale catfish (Rhamdia guatemalensis) is a freshwater catfish reaching up to 30 cm, with long barbels and a body that ranges from normal dark coloring in surface populations to pale, depigmented forms in cave-dwelling populations. Found from central Mexico through Central America to northern South America, it inhabits rivers, lagoons, cenotes, and underground cave systems at depths of 0 to 30 meters. Some cave populations show incipient troglomorphism with reduced pigmentation and smaller eyes, representing early stages of cave adaptation. It is an omnivorous and opportunistic feeder, consuming invertebrates, plant matter, and detritus. Cenote divers in Mexico's Yucatan Peninsula regularly encounter this species in the crystal-clear waters of cenotes and the entrance zones of underwater caves, where its pale form gliding through sunlit cavern passages creates ethereal photographic opportunities.