Agassiz's Corydoras

About

Agassiz's Corydoras (Corydoras agassizii) is one of those species that keeps hobbyists and taxonomists alike on their toes. Native to the upper Amazon basin near the Peru-Brazil border, it belongs to a genus of over 150 armored catfishes whose bony plates give them a distinctive, almost prehistoric look. Identification is genuinely difficult. Color patterns vary enough that fish sold under this name are frequently the similar-looking Corydoras ambiacus, or possibly undescribed species entirely. Typical markings include a yellowish lateral stripe, a partially dark dorsal fin with pale spotted rays, and a bluish-white tail banded with brown spots, though individuals vary considerably. Like all corydoras, these fish are facultative air breathers. They'll occasionally dart to the surface for a gulp of air, which is perfectly normal behavior and not a sign of trouble. The pectoral-fin spines deserve a mention: they're sharp enough to pierce skin and may carry mild toxic secretions from glands at their base, so handle with care when netting. In the aquarium they're peaceful and sociable, doing best in groups of at least four to six. They'll spend most of their time nosing around the bottom, and their habit of tilting an eye downward to inspect the substrate is genuinely endearing. A long-lived genus when well kept, with lifespans that can stretch well past a decade.