Blue Cory

About

Known in the hobby as the blue cory, Corydoras nattereri is a small armored catfish native to coastal river systems along the southeastern Brazilian seaboard, from Espírito Santo down into Paraná. Like all members of its enormous genus, it wears two rows of bony plates instead of scales and carries sharp pectoral fin spines that can catch in nets or deliver a surprisingly painful poke, so handle with care. One of its more endearing quirks is facultative air breathing: it uses a highly specialized section of intestine to extract oxygen from gulped atmospheric air, so you will regularly see individuals darting to the surface for a quick sip. This is completely normal, but a sharp uptick in surface visits usually signals that water quality needs attention. The blue cory is a committed schooling fish, and a group of six or more will be visibly more relaxed, bolder, and active than a lone individual or a small cluster. It does best in a community with other peaceful, similarly sized fish, though its preference for slightly cool water means you will want to think carefully about tankmates. Sinking foods are a must since this species feeds at the substrate level. Kept well, it can live for a remarkably long time, which is something many new keepers do not anticipate when they first pick it up.