Callichthyidae, Subfamily Corydoradinae Common Name:
Emerald Catfish, Emerald Cory Origin and Habitat:
Upper reaches of the Amazon, Rio Ucayali, Rio Ambiyacu, Rio Tocantins, within the countries of Brazil, Columbia, Peru and Ecuador. Occurs in slow-flowing streams and sluggish waters with dense vegetation. Compatibility/Temperament:
Very peaceful bottom feeding fish well suited to any community of non-aggressive fishes. Must be kept in a small group of at least 3 but will be better in groups of five or more. Emerald Catfish Diet
Feeds on worms, insect larvae and small crustaceans in its habitat; readily accepts sinking prepared food such as tablets and pellets, and frozen bloodworms and live worms are relished. Size
Can attain just over 3 inches. Minimum Tank Suggestion
20 gallons, but preferably long (30-inch length) rather than tall. Water parameters for Emerald Catfish
Soft to moderately hard (hardness to 30 dGH), acidic to basic (pH to 8.0) water, temperature 22-28C/71-82F. Description
This fish is often mistaken for a Corydoras
, and it does bear a striking resemblance to C. aeneus
. The common names are often misleading, as both fish are regularly seen under the names Green Cory, Green Catfish, Emerald Cory, etc.
The Corydoradinae sub-family currently contains three genera, Aspidoras, Brochis
, all closely related and near-identical in their requirements and behaviours. Some ichthyologists feel the three genera should be combined into one, others suggest two with the three Brochis species included in Corydoras. At present, there are three species recognized in the genus Brochis
: B. splendens
is the most common, while B. britskii
and B. multiradiatus
are rarely seen in the hobby. Brochis splendens
grows larger than the very similar Corydoras aeneus
, and can easily be differentiated by the deeper body and larger dorsal fin. All Corydoras
have 6-8 rays in the dorsal (Burgess) while B. splendens has 10-12. The other two species have 15-18 rays. The dorsal is therefore much closer to the adipose fin on Brochis
This catfish does best in a well-planted aquarium with several chunks of bogwood on the substrate which should be sand; it appreciates resting spots under the cover of plants or wood. It does not like strong water currents. Brochis
will spend more time on the substrate than the average cory.
The dorsal, pectoral and adipose fins are each preceded by a spine which is actually a hardened and modified ray; the pectoral fin spine can be "locked" into position by the fish; care must be taken when netting these fish not to entangle the spines, which can also give the aquarist a nasty jab. They are believed to be a defense adaptation, to lodge the fish in the throat of a predator.
All species in the sub-family will periodically and fairly regularly swim quickly to the surface for a gulp of air. The fish swallows the air and blood vessels in the hind gut extract oxygen from the air; it is then expelled through the vent the next time the fish breaks the surface for another gulp of air. This adaptation is believed to have evolved so that the fish can survive in poorly-oxygenated water such as drying pools during the dry season. It is however essential to the fish's well-being that it regularly swallows air.
This species was originally described as Callichthys splendens
by F.L. Castelnau in 1855. In 1872, E.D. Cope named the same fish Brochis coeruleus
, and five other names were subsequently assigned to this species. Gosline (1940) suspected the fish were the same species, but it was Nijssen & Isbrucker (1970) who sorted it out, and Brochis splendens
(Castelnau 1855) having priority is now the recognized name with B. coeruleus
The genus name Brochis
is Greek for inkhorn, which the fish resembles; the species epithet splendens
is the Latin "to shine," a reference to the emerald shine reflected under light. Contributing Members
The following members have contributed to this profile: Byron