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Emerald Cory Catfish Care, Tank Setup, Breeding & More

Want to start your aquarium space with awesome fish that’s also easy to care for?  Then, you should put emerald cory catfish on your list. It has gained wider popularity among aquarists for its happy behavior, easy breeding, and the fact that it can help you clean the aquarium.

Emerald Cory Catfish is known as Corydoras Splendens or simply cory catfish. It’s a little South American catfish that can grow only up to three inches in length.

These have been introduced in aquarium environments for a while and no one can resist the charm of this armored catfish.

Species Overview

Level of CareEasy
AppearanceGreenish, bluish reflective body
Life ExpectancyFive years
SizeUp to 3 inches
Tank Size20-gallons
Tank EnvironmentFine substrate, dense plant, fully covered
Tank MatesKept in groups

Emerald Cory Catfish or Corydoras Splendens is a member of the South American catfish species. They’re renowned to have adorable personalities but also heavily armored bodies with sharp spines that could be venomous when they’re threatened. This feature provides them with protection against predators.


Corydoras or Emeraldis also widely known as Emerald Green Cory while others may call it Green Catfish. While indeed they reflect green color, the lighting may enable the body to reflect the metallic blue. That’s why some people also call this fish the Blue Catfish, which refers to Brochis coeruleus.


These have an adorable appearance with great details that pampers aqua die-hard fans. The beauty has an emerald green body that looks iridescent and you can notice their lower body has pink highlights to contrast the upper parts.

Behavior & Temperament

Catfish usually live in groups of tens or hundreds of the same species. They’re particularly active in the daylight until dusk and dawn. Emerald catfish is a popular corydoras along with albino cory, bronze cory, pygmy cory, and panda cory,

While they’re typically active in the daylight, you might also find them become motionless in the same spot for a while as they’re resting.

This behavior is kept when they are transferred to an aquarium environment. You can enjoy their activeness during daytime hours and their mild movements at night.

Corydoras splendens are certainly bottom dwellers. They would spend most time scavenging the bottom part of the tank to eat scattered foods. Don’t get it wrong, these could be very active, especially in the daylight.

The Emerald cory catfish, despite its charming appearance, is quite timid than other comparable catfish.

Some aquarists argue that it refers to its size relative to the tank mates in a community aquarium aka intimidated. However, it also informs us that we need to work on a specific tank setup and develop suitable dynamics for them.


Emerald can live up to five years in a well-controlled tank with proper water conditions. However, aquarists are haunted by a high case of immediate death after tank introduction. It’s apparently because of the extreme gap in water conditions in the store display tank and home tank.

That’s why you need to properly condition the water parameters in the tank and avoid those lethal gaps. At this point, preparing the species or community tank has become more crucial if you’ve decided to keep these. Do your research on this matter to prevent your Emerald catfish from dead immediately after relocating to your tank.

Emerald corydoras splendens at tank bed

Care & Tank Setup

Tank Size

Emerald is a quite small fish species that can live well in a 10-gallon tank. Of course, larger tanks provide them with space to swim and you with the flexibility to add tank mates and decorations.

At this point, you can consider the bio-load capacity of the tank and the number of specimens you want to add to the tank.


Don’t overpopulate the tank and consider the proper treatment you need for the tank size. They would typically dart up to the tank surface to grab some air or food and back to the bottom at the speed of sound. That’s why you need to fully cover your tank but don’t worry about this behavior.

Since Emerald cory catfish should be kept in groups, a 20-gallon aquarium is ideal instead of taking risks with a 10-gallon tank. A species tank can have a group of six green corydoras which is the most recommended configuration for the species tank.

The bottom dwellers can live peacefully with other community fish that do not attack or prey on them. The tank mate selection, however, should be done carefully to keep the well-being in the community tank. If you’re not sure about a community aquarium, you can always start with a specific tank.

When the community tank comes to your mind, you should get the most out of it. As these are the bottom dwellers that occupy the below part of the aquarium, you can choose species that occupy the middle part and upper part of the community tank.


Like other bottom-dweller species, the tank for Emerald cory catfish would need fine sand or gravel so they can feed more easily. These won’t trap the foods you’ve provided and they can easily grab them.

At this point, the texture of foods should also be considered where Repashy gel foods, worms, and other larger foods are highly recommended.

The bottom-dweller needs a proper bottom setup. You can add around 2-inch of substrate or gravel to the bottom of the aquarium.

Add more live aquarium plants that would work as their hiding places and keep your fish less stressed. Enrich your decorations with caves, rocks, or other underwater fixtures for bottom-dwelling exploration.

Water Parameters

Emerald cory catfish can thrive in a wide range of water conditions but the ideal ones can make them happier and live longer. You can maintain the water temperature of 72 – 78 F while keeping the pH level around 7.0 -7.8 for the best possible water conditions. You can also add community tank lighting for the aquarium.

The water conditions could be subject to the biodiversity in the community tank but you need to manage the stability for goods.  Do regular partial water changes to control the Nitrate buildup and ensure the Nitrite and Ammonia level holds at 0 ppm. Prevent any extreme or sudden shifts in the water conditions.

They can be sensitive to frontal water changes and poor water conditions. These would make them susceptible to diseases and even lethal infection. The catfish can be stressed out following the high nitrates content in the aquarium.

On the other hand, the bottom substrates or gravel may pile up decaying organic matter including from the uneaten foods.

At this point, you must not stir up the bottom substrate that may release hazardous substances into the water that can lead to lethal bacterial infections. The infected ones may stop eating and die without treatment.

Emerald Cory Catfish Tank Mates

Emerald cory catfish are like other catfish that have social behavior. You can even find them thriving in the aquarium alone. However, you can keep a group and they’d be happier and typically live longer.

They are schooling bottom-dweller even though not so active compared to those middle dwellers. You’d find them group or be close to each other in the tank. They can even hang out very well with other catfish species.

Once you use a larger tank, you’d see a group of six or eight of these schooling around. It’s very interesting and eye-pampering to see how these bottom-dwellers school in groups.

When it comes to community tanks, the main idea is to provide Emerald cory catfish with friendly, non-aggressive species. Some species you can consider include other corydoras species, swordtails, and tetras. Some freshwater shrimps and snails could be adorable tank mates and diverse aquarium appeal.

Food & Diet

Emerald catfish aren’t picky on food and they love anything that fits in their mouth. You can feed them with frozen bloodworm, live blackworms, gel foods, sinking species/community foods, Vibra bites, etc. A varied diet is best.

Another rule you should follow to prevent decreased water quality is not overfeeding. No matter how active the bottom-dwellers in searching for their foods in the ground, there would be uneaten foods if oversupplied. The trapped leftovers would rot and contaminate the water which decreases its quality.

What is more amazing is to witness how Emerald cory catfish, despite their shy nature, can comfortably eat food next to their tank mates. They may share food pellets with no problems. Regardless of the excitement, you need to ensure the best possible tank mates.

Breeding Guidelines

Emerald cory catfish can be bred in captivity with no problem with a breeding tank and fry tank. You can set up the breeding tank with little to no substrate and allow them to spawn there. Preventing parents from eating the eggs, you can remove the adults and let the fry thrive in the breeding tank.

Another way to breed them is by transferring the fertilized eggs to a separate tank for fry from the main tank. It’s a more practical method even though it may decrease the number of surviving fry that hatches from the eggs. Either way, you want to do it properly to have a new generation of your Emerald green corydoras.