The Emerald Green Cory Catfish Corydoras splendens (previously Brochis splendens) is a beautiful and interesting fish. It typically has an iridescent, emerald-green body with pink highlights on the lower parts of the fish.

It’s also called Emerald Green Cory or Green Catfish, as well as Iridescent Plated Catfish. Depending on the light, this fish can appear a metallic blue or an emerald green. At one time, due to its pretty blue coloration, it was described as Brochis coeruleus and so it is called Blue Catfish as well.

This is one of three fish that have been known as the Brochis catfish, and are very similar to each other. They strongly resemble other Corydorus, but are larger and have more rays in the dorsal fin. The other two are the Britski’s Catfish Corydoras britskii and the Hognosed Brochis Brochis multiradiatus. Until just recently all three were classified in the Brochis genus, but currently the Hognose is the only one still in that genus.

The Emerald Green Cory is the most commonly available in the pet industry of these three, and is sometimes referred to as the “common brochis.”. It is a smaller member, generally reaching between 2 3/4 – 3 inches (7 – 8.4 cm) in the aquarium, though a large female can reach about 3 1/2 inches (9.0 cm). The largest of these three are the Britski’s Catfish which readily reaches 3 1/2 inches. All three are from South America and have virtually the same maintenance and feeding requirements.

Despite their size Emerald catfish are very peaceful and can be recommended for a community aquarium. They are quite shy and easily frightened when kept as a single fish however. They really need to be kept in a group of at least 6 individuals, and will be happiest in a school of 10 or more. Size-wise they could be kept in a 20 gallon tank, but when keeping a group, 30 gallons or more is best. In a community tank, other companions must also not be too large, or overly aggressive.

These fish are quite hardy and make a great fish for beginners. They do need clean, well-oxygenated water and plenty of food on the bottom of the tank. They’re semi-active and will spend most of their time in the lower regions of the aquarium scavenging for uneaten food. These catfish are known for their great skill at keeping the substrate clean, however, that should not be their only source of food and the substrate should be vacuumed with each water change.

Emerald Green Cory


Scientific Classification


Emerald Green Cory – Quick Aquarium Care

Aquarist Experience Level:Beginner
Aquarium Hardiness:Moderately hardy
Minimum Tank Size:30 gal (114 L)
Size of fish – inches3.5 inches (8.99 cm)
Temperature:68.0 to 82.0° F (20.0 to 27.8&deg C)

Habitat: Distribution / Background

The Emerald Catfish Corydoras splendens (previously Brochis splendens) was described by Castelnau in 1855. They are found in South America it the upper Amazon inhabiting rivers, tributaries and standing waters. They have a wide distribution; Brazil in Iquitos and Rio Tocantins; Ecuador in Rio Napo; and Peru in Rio Ucayali, Rio Napo, Rio Maranon, and Rio Amplyacu. Other common names they are known by include Emerald Green Cory, Iridescent Plated Catfish, Emerald Brochis, Blue Catfish, Green Catfish, Common Brochis, Shortbody Catfish, and Armored Catfish.

The Emerald Green Cory is one of three fish that have been known as the Brochis catfish, and they are very similar to each other. The other two are the Britski’s Catfish Corydoras britskii and the Hognosed Brochis Brochis multiradiatus. Until just recently all three were classified in the Brochis genus, but currently the Hognose is the only one still in that genus. There is an interesting deliema here. The Emerald Catfish, now placed in the other Corydorus genus, is actually the “type” species for the Brochis genus, so how this will be finalilzed remains to be seen.

In their natural habitat schools of Emerald Green Cories live in shallow waters with a muddy substrate and heavy aquatic plant life. They prefer oxygen enriched waters but will swim to the surface and gulp air if needed. They are demersal and feed on worms, insect larvae, small crustaceans, and some plants. They are found in shoals or schools of fish.

  • Scientific Name: Corydoras splendens
  • Social Grouping: Groups – In the wild, they live in shoals or schools. The more the merrier!
  • IUCN Red List: NE – Not Evaluated or not listed


The Emerald Catfish is a larger member of the Corydoras family, reaching between 2 3/4 – 3 inches (7 – 8.4 cm) in length in the aquarium, though a large female can reach about 3 1/2 inches (9.0 cm). They have a lifespan of up to 13 years in a properly maintained aquarium.

These are beautiful fish that appear to change colors from the reflections of the light and decor and can be seen as a metallic green, blue-green or a deep blue. The pectoral, ventral, and anal fins are all yellow with the dorsal, caudal and adipose fins being brown. Females normally have pinkish undersides and males have more of a yellowish underside.

This fish belongs to the catfish family Callichthyidae, and like all catfish they are scaleless. Corydoras are known as armored catfish because they have two rows of bony plates, called scutes, along the length of the body. They also have 6 pairs of barbels around the mouth and strong, rigid spines on their dorsal and pectoral fins. Corydoras have also been known to produce sounds of warning when distressed and when courting. They make sounds by rubbing the spines of their pectoral fins into the grooves of their shoulder plates.

The Emerald Catfish is larger with a thicker body and more of a pointed snout then many of the similar Corydorus species. It is one of three fish that have been known as the Brochis catfish, and they are very similar to each other. The other two are the Britski’s Catfish Corydoras britskii and the Hognosed Brochis Brochis multiradiatus.

These three species strongly resemble other Corydorus, but are larger and have more than 10 dorsal fin rays as opposed to 7 rays for the smaller cories. The Emerald Catfish can be distinguished from the other two because it has the fewest dorsal fin rays, 10 – 12. The the Britski’s catfish C. britskii has 15-18, normally 15. The Hognosed Brochis B. multiradiatus usually has 17-18 and it has a longer snout than either of the other two. The Britski’s catfish is very similar to the Hognosed Brochis, though with the shorter snout. But can be distinguished by an upper forehead that is more convex, dipping in slightly, while the Hognosed’s upper forehead is concave. It is also unique in that it has a bony shield covering the underside of its head.

  • Size of fish – inches: 3.5 inches (8.99 cm) – Females tend to be larger than males.
  • Lifespan: 13 years – They can live for 13 years with optimal conditions.

Fish Keeping Difficulty

The Emerald Green Cory is not a difficult fish to care for. They are quite durable and great for beginners. Being gregarious fish, they need to be kept in a school of at least 6 individuals but will be happiest in groups of 10 or more. When kept singly they are quite shy and easily frightened. They are very peaceful and do great in a community tank but will not thrive with aggressive fish.

These catfish need clean water that is high in oxygen and a good supply of food on the bottom of the tank. A good filtration system will maintain clean water and provide water movement at the surface for keeping the oxygen level up. If the tank is not established make sure to add sinking pellets for food. These fish do a great job keeping the bottom cleaned of food and debris, but the substrate still needs to be vacuumed regularly.

Be careful when netting them because when they feel threatened, Corydoras will extend their sharp spined fins outward and lock them in a rigid position. The spines are quite sharp and can pierce your skin.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

Emerald Catfish are omnivores that feed on worms, crustaceans, insect larvae, and plant matter in the wild. In the aquarium they are easy to feed and will generally accept all kinds of live, fresh, and flake foods. To keep a good balance give them a high quality sinking pellet or flake food everyday. Also offer occasional algae wafers. Feed frozen and live food, such as brine shrimp, blood worms, or daphnia as a treat.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes – This fish will happily clean up leftover food from the fish in higher parts of the tank, however if this is not in ample supply, this fish appreciates the offer of sinking carnivore pellets or tablet food.
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Daily – Feed as much as they will eat in about 5 minutes. They can be fed twice a day, offering as much as they will consume in about 3 minutes each.

Aquarium Care

Regular water changes with siphoning of the gravel is crucial to remove their waste and keep the tank clean. A weekly or bi-weekly water change of 10% to 20% is recommended. These catfish spend most of their time on the bottom and their barbels are prone to infection from a poorly kept substrate. Using a vacuum hose to siphon the substrate is a good way to keep the gravel free of decomposing animal and plant matter.

These fish do best with strong filtration that also helps keep the water highly oxygenated. If oxygen levels drop these fish will swim to the top and gulp air and then swim back down. Excessive gulping may be an indication that the water needs more oxygenation.

  • Water Changes: Weekly – Weekly or bi-weekly water change of 10% to 20% are recommended.

Aquarium Setup

The Emerald Green Cory is a semi-active fish that needs to be kept in a group of 6 or more individuals. A 20 gallon tank would work for a single fish, but they really need to be kept in a school. A minimum tank size of 30 gallons with near neutral pH is recommended. Normal lighting works well as this fish is more likely to be out during the day, unlike most Corydoras that need more of a subdued tank lighting. High light levels are fine if plenty of shade is provided.

The aquarium should be decorated and arranged with their natural habitat in mind. These fish enjoy well planted tanks with twisted roots to hide in. Caves and drift wood make great hiding spots as well. Because these fish have sensitive barbels it is preferable to have a small, smooth gravel to keep their barbels in good condition. These barbels are prone to infection from a poorly kept substrate. An undergravel filter works best for this fish to keep the substrate clean and the entire tank oxygenated.

  • Minimum Tank Size: 30 gal (114 L) – Because they require a group of conspecifics to thrive, a minimum of 30 gallons is recommended. Individual fish can be kept in a 20 gallon aquarium but will generally be shy, retiring, and easily frightened when kept by themselves.
  • Substrate Type: Small Gravel – A small, smooth gravel is best to protect their barbels from damage.
  • Lighting Needs: Moderate – normal lighting
  • Temperature: 68.0 to 82.0° F (20.0 to 27.8&deg C)
  • Range ph: 5.8-8.0
  • Hardness Range: 2 – 15 dGH
  • Brackish: No – This catfish can be sensitive to any salt levels.
  • Water Movement: Moderate
  • Water Region: Bottom – They will mostly swim at the bottom of the aquarium.

Social Behaviors

The Emerald Green Cory are considered a peaceful community fish and can be kept with most other types of community fish that are peaceful and not too large. They are not aggressive and are good with tankmates that are peaceful and not too large. Small peaceful community fish such as live bearers, small members of the Tetra family, Danios, Rasboras, and Dwarf Cichlids all make good tank mates. They will not fare well with aggressive fish.

They are gregarious and enjoy the company of there own kind. In fact they are so very sociable that they need to be kept in schools of at least 6 individuals, but are happiest in groups of 10 or more. When kept singly they are very shy, reserved, and easily frightened which results in stress.

  • Venomous: No – Corydoras species have spines that can cause a stinging sensation if they penetrate the skin.
  • Temperament: Peaceful
  • Compatible with:
    • Same species – conspecifics: Yes – This sociable fish is happiest in a group of at least 6, but do best in groups of 10 or more.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Monitor
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Safe – Corydoras feed at the bottom of the aquarium, so are not in competition with other feeders.
    • Shrimps, Crabs, Snails: May be aggressive – The natural diet of Corydoras are worms, crustaceans, and insects.
    • Plants: Safe – May eat some plants, but algae rather than plants is more palatable to them, though they may uproot some plants while foraging.

Sexual differences

Sexing is difficult and breeding is best accomplished by natural pairing. Females are usually larger then the males when mature, and have thicker bellies when carrying eggs. Females may also have a more pinkish colored belly while the male’s will be yellow.

Breeding / Reproduction

Although the Emerald Catfish are considered difficult to breed, aquarium spawnings are fairly common. They are considered difficult because spawning is probably seasonal, or at least weather related. The necessary conditions are not usually met in home aquariums so inducing spawning can be difficult. The resulting number of fry is usually not very large because the eggs are particularly prone to fungus and many of the larvae perish.

The spawning tank needs to have some substrate and some floating plants. Breeding can be induced by lowering the water level and introducing colder water to get spawning to start. They spawn much like other Corydoras close to the bottom. The males initiate courting, swimming over and around the female. Eventually they form a t-position or lay side-by-side. The female will release about 12 eggs and adamantly bump the male’s ventral fin causing him to release sperm. The female will gather the fertilized eggs into a nest formed with her pelvic fins and then place them individually on plants, rocks, driftwood, and other objects. She will go back to the male and repeat the process until the spawn is complete.

Spawning pairs have been known to produce 900 to 1,100 eggs. The eggs are very prone to fungus, so anti-fungal additives will probably be needed. The eggs will hatch in about 4 days after spawning. Fortunately when well fed, the parents do not eat the eggs.

In the first days after hatching the young are very sensitive to water deterioration and many may die at this time. Frequent water changes and substrate siphoning can help. The fry begin to color in about 10 days, but the characteristic emerald green doesn’t show up until the fry are 6-7 weeks old. The fry should initially be fed protozoan organisms in the aquarium. As they grow, they will be able to accept foods such as baby brine shrimp. See the description of how to breed these fish in the section on Corys in Breeding Freshwater Fish: Catfish.

  • Ease of Breeding: Difficult – Lowering the water level and adding cold water will sometimes induce spawning.

Fish Diseases

Emerald Catfish are very hardy and disease is not usually a problem in a well-maintained aquarium. There is no guarantee that you won’t have to deal with health problems or disease, but cory catfish are very resilient.

High nitrate levels can cause them to develop infected barbels; this makes it difficult for them to navigate and eat normally. Maintain nitrate levels below 20 ppm through regular water changes. Because they are a scaleless fish, catfish can be treated with pimafix or melafix but should not be treated with potassium permanganate or copper based medications. Malachite green or formalin can be used at one half to one-fourth the recommended dosage. All medications should be used with caution.

The best way to proactively prevent disease is to give your fish the proper environment and give them a well-balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish will is more likely to acquire disease. Anything you add to your tank can bring disease with it. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so as not to add new diseases to the tank. For information about fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Emerald Green Cory or Emerald Catfish are readily available and moderately priced. Juveniles will have a mottled color pattern and they are sometimes sold as ‘hi-fin corydoras’ because of their enlarged dorsal fin.



Featured Image Credit: chonlasub woravichan, Shutterstock