Common Names: Emerald catfish, common Brochis, emerald cory
Type Locality: Rio Tocantins, Brazil
Range: Amazon River Basin
Taxonomic Troubles: Originally described as Callichthys splendens. Has been known by a variety of names, including B. coeruleus, B. dipterus, Chaenothorax bicarinatus, Chaenothorax eigenmanni, and Corydoras semiscutatus.
Size: 8 cm (3 inches) TL.
Preferred Water Chemistry: Tropical freshwater; as with most fishes with large natural ranges, this species is quite adaptable to non-extreme water chemistries.
Difficulty: A very hardy species. Must be kept in schools.
Tank Setup: Most of the time a school of these catfish will be foraging in the substrate, so a lot of open area is important, but they like to occasionally rest in spaces under driftwood or rocks.
Feeding: Primarily a predator of small invertebrates. Will accept just about any food but is especially fond of live worms.
Breeding: Breeds in typical cory fashion, fastening eggs at the waterline. Young are not difficult to raise and go through a sequence of major changes in coloration, with the intermediate juvenile covered in dark spots and sporting red fins.
At first glance this Brochis could be confused with the old favorite Corydoras aeneus, but besides growing larger, it has a larger dorsal fin and a more lyrate caudal, is more high-bodied, has a longer snout, and displays more intense and changeable coloration. Under ideal conditions this fish shines—hence the common name “emerald.”
The intense, iridescent green of a Brochis splendens in good shape is best appreciated in person. Fortunately, keeping a school of these animals happy is not difficult—all they need is enough room, a suitable substrate for rooting around in, clean water, and a varied diet. Perpetually active, they are peaceful fish whose size nevertheless enables them to better tolerate other species that might harass their smaller cousins, the Corydoras. Although this species has been available in the hobby for a very long time, it has never gained the popularity it deserves.