Armored Catfish (Callichthyidae)

Corydoras melanotaenia

Corydoras melanotaenia, also known as the Rainbow Corydoras (scientific name Corydoras melanotaenia), belongs to the family Callichthyidae, or armored catfishes. This catfish is native to South America, where it inhabits the Meta River basin—a large tributary of the Orinoco, located in Colombia and Venezuela. In nature, these fish are found in small tributaries, streams, on sandy shoals, and in areas of flooded forest.

Tank
from 80 L (21 gal)
Temperature
20 – 23 °C (68 – 73 °F)
Size in aquarium
6 cm (2.4 in)
Acidity
pH 6–7.2
Natural rangeRange on the map
  • Colombia

Tank conditions

Plan the tank stocking
Temperature
20 – 23 °C (68 – 73 °F)
Water pH
Slightly acidic (6) – Neutral (7.2)
Water dH
Very soft (2) – Hard (15)
Water salinity
no salt (freshwater)
Size in aquarium
6 cm (2.4 in)
Lifespan
5 years
Temperament
Peaceful, calm/shy/inactive
Toward small fish
not a predator
Required aquarium volume
from 80 L (21 gal)
Lighting
dimmed or moderate
Substrate
soft silted
Water flow
weak or moderate
Swimming level
near the bottom
Feeding
Sinking (any)
Keeping
Small group 5–6 individuals
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (small group (5–6 individuals)), footprint, decor and tank mates.

Care and keeping

Description

Adults grow to approximately 6 cm in length. Their appearance is typical of armored catfishes: the body is protected by two rows of bony plates instead of ordinary scales, and the first rays of the pectoral fins are modified into sharp spines. Although at first glance they resemble Golden Corydoras, upon closer inspection, Corydoras melanotaenia exhibit characteristic golden-yellow hues that shimmer into green tones. As with most Corydoras, determining the sex of these fish is quite difficult, as males and females are practically identical in external characteristics.

Habitat

The species is endemic to the Meta River basin in Colombia. In nature, it inhabits small tributaries, streams, as well as flooded forest areas and sandy shoals. It prefers areas with soft substrate and moderate current, where the water may be stained a weak tea color by organic matter.

Behavior and Compatibility

These fish are distinguished by their particular peacefulness and calm disposition. They are schooling fish, so it is recommended to keep a group of at least six individuals in aquariums. They coexist well with most other aquarium fish species of comparable size. However, since they are bottom dwellers, care should be taken to avoid keeping them with territorial species, such as some loaches or other catfishes.

Care and Maintenance

For keeping six catfishes, an aquarium of at least 80 liters will be optimal. The setup should preferably include a sandy substrate, several natural snags, and dense thickets of live plants. Tree bark and leaves can also be placed on the bottom. These fish prefer subdued lighting and often hide during the day, becoming active mainly at dusk or night. They are capable of using atmospheric air for breathing, rising to the surface for a gulp, so it is important to leave open water areas free of floating plants. Corydoras melanotaenia are not particularly demanding regarding water parameters; they adapt well to a wide range of pH and GH values, but still prefer a softer and more acidic environment. However, they are sensitive to pollution by organic waste, such as food remnants and excrement, which can lead to diseases and damage to their sensitive barbels. Therefore, it is necessary to regularly, at least once a month, clean the substrate of accumulated deposits. These catfishes are omnivorous and readily accept most popular foods. Natural foods such as fresh, frozen, or dry daphnia, bloodworms, Artemia, and other zooplankton will be an especially good choice.

Diet

Corydoras melanotaenia are omnivorous and readily accept most popular types of food. Natural foods such as fresh, frozen, or dry daphnia, bloodworms, Artemia, and other zooplankton will be an excellent choice.

Breeding and Reproduction

Under suitable conditions, Corydoras melanotaenia breed quite frequently. It should be noted that these catfishes do not exhibit parental care. For successful breeding, it is recommended to use a separate spawning tank to protect the eggs and fry from being eaten by adult fish. More detailed information on breeding Corydoras in home aquariums can be found in a specialized article.

Diseases

Fish are sensitive to water quality and substrate cleanliness. When kept in unsanitary conditions or on contaminated substrate, individuals often show erosion and damage to their barbels, which can lead to secondary bacterial infections. Prevention includes regular water changes, gravel vacuuming, and the use of soft sand to prevent injury to their delicate sensory organs.

How to choose

When choosing, attention should be paid to the integrity of the fins and the absence of damage in the barbel area. Healthy individuals should be active, show interest in foraging for food in the substrate, and have no signs of emaciation or spots on the body. When purchasing, it is important to consider that fish feel most comfortable in a group, so it is recommended to acquire at least six individuals to reduce stress levels.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Corydoras melanotaenia get?

An adult reaches 6 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Corydoras melanotaenia need?

The recommended volume is 80 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Corydoras melanotaenia need?

Temperature 20–23 °C, pH 6–7.2, hardness 2–15 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Corydoras melanotaenia live?

Around 5 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Corydoras melanotaenia aggressive?

Temperament: peaceful, calm/shy/inactive. Keep this in mind when choosing tank mates.

How many Corydoras melanotaenia should be kept together?

Recommended setup: small group (5–6 individuals). Ignoring this is a common cause of stress and disease.

What does Corydoras melanotaenia eat?

Diet type: sinking (any). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Corydoras melanotaenia?

The scientific name of the species is Corydoras melanotaenia, family Armored Catfish (Callichthyidae).

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Other scientific names and conservation status

Conservation status
Least concernLC