Corydoras Catfish Care Guide

The two care details most often skipped for corydoras, keeping a real group rather than a token pair, and choosing genuinely smooth substrate, are also the two most consequential for long-term welfare in this species specifically.

Group Size

Corydoras are shoaling fish that show visibly more confident, natural foraging behavior in groups of six or more of the same species; a single fish or pair survives but shows more hiding and reduced activity. A 20-gallon tank comfortably houses a starting group of six smaller corydoras species.

Substrate

Smooth, rounded sand or well-chosen fine, rounded gravel is a genuine requirement rather than a cosmetic choice, since corydoras use sensitive facial barbels to feel for food in the substrate constantly, and sharp-edged gravel wears these down over time, leading to chronic, low-grade barbel damage that's easy to miss until it's advanced. Checking gravel by rubbing a handful between your fingers for roughness is a simple pre-purchase test.

Water Parameters

Most commonly kept species (bronze cory, peppered cory, sterbai cory, and similar) do well across 72-78°F and pH 6.5-7.5, with soft to moderately hard water (2-15 dGH). As with any fish, ammonia and nitrite should be kept at zero.

Normal Surface Air-Gulping

Corydoras periodically dash to the surface, gulp air, and return to the bottom as part of normal intestinal air-breathing, an adaptation to low-oxygen wild habitats. This is healthy behavior, not a sign of distress, though a marked increase in frequency beyond the individual fish's normal pattern is still worth checking against water quality.

Medication Sensitivity

Because corydoras are scaleless, they're more sensitive than scaled fish to certain medications, particularly copper-based treatments and some dyes. Always check medication labels for scaleless-fish warnings before treating a tank containing corydoras, and consider removing them to a separate container during a treatment not labeled safe for the species if in doubt.

Diet

Sinking wafers or pellets formulated for bottom feeders, supplemented with occasional live or frozen food (bloodworms, daphnia), suit corydoras well. They are not purely scavengers living on leftover flake, and should be specifically target-fed rather than relying solely on what other fish miss.

See also: Corydoras Catfish Tank Mates, Corydoras Catfish Hub.