Emerald Cory

With a metallic sheen that shifts from green to bluish green under light, the emerald cory is one of the most eye-catching armored catfish. At first glance it resembles the bronze cory, but it has clear differences: a deeper, larger body (7–8 cm) and a long dorsal fin made up of many more rays. While the dorsal fin of corydoras is short and triangular, in Brochis the fin extends over a larger area along the back.

Long known under the name Brochis, the species was for a time moved to the genus Corydoras and has been returned to Brochis in recent classification studies; both names may be encountered in stores. Its care is almost the same as for corydoras.

It lives in slow-flowing, vegetated waters with muddy-sandy bottoms in the upper and middle Amazon basin, such as lake and swamp margins and still backwaters. These habitats are warm and at times low in oxygen; the fish tolerates this because it can take oxygen from the air through its intestine.

• Volume: at least 100 liters for a group of 5–8; a base length of 80–100 cm.
• Substrate: fine, rounded sand.
• Water: 22–28°C; soft to moderately hard, it adapts to a wide pH range.
• Decor: roots, plants and a large open sand area. It must be able to reach the surface easily to gulp air.

Sinking tablets and granules, frozen bloodworms, brine shrimp, tubifex. Being larger than corydoras, it easily eats bigger tablets. Food given in the evening reduces competition with other fish.

A peaceful, calm bottom dweller. In a group the fish forage on the bottom and often rise to the surface to gulp air. Despite its size it does not harm fish or shrimp.

Good companions: medium-sized tetras, peaceful barbs, gouramis, angelfish, dwarf cichlids, other corydoras.

Avoid: aggressive cichlids that claim the bottom, large predators.

At least 5, ideally 8 or more individuals. In a large group it is more active and visible. It can roam together with corydoras, but a group of its own species lets it behave more comfortably. Because of its size, the need for floor space increases quickly as the group grows; 120 liters or more is more comfortable for a group of 8.

Breeding in the aquarium is less frequent than with corydoras. In successful attempts the eggs were laid on the undersides of plant leaves and on the glass. The eggs hatch in a few days; the fry are raised on microworms and freshly hatched brine shrimp.

• Barbel erosion: sharp or dirty substrate.
• It is sensitive to nitrate buildup; regular water changes are essential.
• It is sensitive to salt and copper-based medications; lower the dose when treating.
• Quarantine: observing newly arrived fish in a separate aquarium for 2–3 weeks prevents diseases from being carried into the main aquarium.

Females are larger and plumper, with broader bellies when viewed from above. Males are smaller and slimmer.