Emerald Catfish Care Guide: Tank Setup and much more – 2021

Emerald Catfish


Emerald Catfish Introduction


Want to start your aquarium space with awesome fish that’s also easy to care for?  Then, you should put emerald 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 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.

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


Category Rating
Level of care Easy
Temperament Peaceful
Appearance Greenish, bluish reflective body
Life expectancy Five years
Size Up to 3 inches
Diet Omnivore
Family Callichthyidae
Tank size 20-gallon
Tank environment Fine substrate, dense plant, fully covered
Tank Mates Kept in groups


About Emerald Catfish


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


Emerald Catfish Behavior


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 Emerald catfish is 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, Corydoras splendens or emerald catfish could be very active especially in the daylight.

Emerald catfish, despite its charming appearance, is quite shy and timid than other comparable catfishes.

Some aquarists argue that it refers to its size relative to the tankmates 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 Corydoras splendens.


Natural Environment


Emerald share a similar natural environment with most cory species. In general, they love warmer water with a temperature of 72 to 82 F.  It also prefers a little bit of acidic water with pH values of 6.5 to 7.8. There’s no difficulty to replicate this environment with aquarium tools available in the market.


Emerald Catfish Appearance


Corydoras splendens has 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.

Corydoras splendens 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.


Emerald Catfish Lifespan


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 of 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 Emerald catfish. Do your research on this matter to prevent your Emerald catfish from dead immediately after relocating to your tank.

Caring and Tank Guide of Emerald Catfish


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. Emerald 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 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 Emerald catfish which is the most recommended configuration for the species tank.

The bottom dwellers can live peacefully with other community fishes that do not attack or prey on them. The tankmate selection, however, should be done carefully to keep the well-being of Emerald catfish 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 across your mind, you should get the most of it.  As Emerald catfish 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 for other bottom-dweller species, the tank for Emerald catfish would need fine sand or gravel so they can feed more easily. These won’t trap the foods you’ve provided and Emerald catfish 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 Emerald catfish less stressful. Enrich your decorations with caves, rocks, or other underwater fixtures for bottom-dwelling exploration.


Water Parameters


Emerald catfish can actually 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.

Emerald catfish can be sensitive to frontal water changes and poor water conditions. These would make Emerald catfish 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 Emerald catfish may stop eating and die without treatment.

Emerald Catfish Tankmates


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

Emerald catfish is a schooling bottom-dweller even though not so active compared to those middle dwellers. You’d find Emerald catfishes would 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 Emerald catfishes schooling around. It’s very interesting and eye-pampering to see how these bottom-dwellers schooling in groups.

When it comes to community tanks, the main idea is to provide Emerald 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 tankmates for Emerald catfish and diverse aquarium appeal.

Emerald Catfish Food


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 for your Emerald catfish.

Another rule you should follow to prevent decreased water quality is not overfeeding your Emerald. 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 that decreases its quality.

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


Emerald Catfish Breeding guideline


Emerald 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 fry thrive in the breeding tank.

Another way to breed Emerald is by transferring the fertilized eggs to the 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 catfish.