Corydoras Catfish Identification Guide
Recognizing the arched armored body, paired bony plate rows, and barbeled snout shared across Corydoras species.
Read the full Corydoras Catfish encyclopedia entry →
Key identification features
- Small, stocky body with a distinctly arched back and flattened belly, rarely exceeding 3 inches (7-8 cm)
- Two overlapping rows of bony armor plates (scutes) running along each flank instead of true scales
- Short, downturned mouth with two or three pairs of barbels for sensing food in sediment
- A short, hard leading spine at the front of both the dorsal and pectoral fins
- Coloration and pattern vary enormously by species — spots, stripes, solid colors, or mottling — but body shape and armor are consistent across the genus
Common look-alikes
- Otocinclus catfish — much smaller, slimmer, sucker-mouthed, without the double armor-plate rows
- Brochis and Aspidoras catfish (close relatives) — similar armored shape but with a higher fin-ray count and rounder profile
- Loaches — lack bony plates entirely and have smooth or scaled skin with more elongated bodies
Where you'll see one
This large genus (100+ species) is native to slow-moving streams, floodplains, and quiet backwaters across South America, especially the Amazon and La Plata basins. Corydoras forage in loose groups along sandy or leaf-littered bottoms, periodically darting to the surface to gulp air.
Frequently asked questions
What single feature confirms a fish is a Corydoras?
The double row of bony armor plates along the flanks combined with an arched back and downturned barbeled mouth.
How do I tell Corydoras from Otocinclus?
Corydoras are larger-bodied with armor plates and multiple barbels, while Otocinclus are slender, tiny, and have a round sucker mouth without plates.