Armored Catfish (Callichthyidae)

Mosaic Corydoras

Corydoras haraldschultzi

The scientific name Corydoras haraldschultzi indicates that the Mosaic Corydoras, or Harald Schultz's Corydoras, belongs to the family Callichthyidae. The catfish received one of its names thanks to the Brazilian fish exporter Harald Schultz, who made this species popular in aquaristics. This species originates from the Guaporé River basin (Portuguese: Rio Guaporé), located in the Amazon. The river flows through both Brazil and Bolivia, forming a natural border between these countries in certain sections. It inhabits small tributaries of larger rivers, as well as streams, backwaters, and small lakes that form when forest areas are flooded. The aquatic environment in these places is characterized by a high content of dissolved tannins, which gives it a characteristic rich brown hue.

Tank
from 100 L (26 gal)
Temperature
24 – 28 °C (75 – 82 °F)
Size in aquarium
6 – 8 cm (2.4 – 3.1 in)
Acidity
pH 5.5–7.5
Natural rangeRange on the map
  • Guaporé River basin
  • Bolivia
  • Brazil

Tank conditions

Plan the tank stocking
Temperature
24 – 28 °C (75 – 82 °F)
Water pH
Slightly acidic (5.5) – Neutral (7.5)
Water dH
Very soft (2) – Medium hardness (10)
Water salinity
no salt (freshwater)
Size in aquarium
6 – 8 cm (2.4 – 3.1 in)
Lifespan
5 years
Temperament
Peaceful (regular)
Toward small fish
not a predator
Required aquarium volume
from 100 L (26 gal)
Lighting
dimmed or moderate
Substrate
sandy (regular, light)
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 can reach approximately 8 cm in length. The body pattern is formed by numerous dark speckles, many of which merge, creating an intricate ornament and forming irregular stripes. The main body color has a slight pinkish tint, most noticeable in the abdominal area. Sexual dimorphism in this species is weakly expressed; males are almost indistinguishable from females, except that females may be slightly larger.

Habitat

The Mosaic Corydoras inhabits South America, primarily in the Guaporé River basin, which flows through Brazil and Bolivia. In nature, it lives in slow-flowing tributaries, streams, flooded forest areas, and small floodplain bodies of water. The water in these biotopes is often saturated with tannins, which gives it a characteristic brown hue.

Behavior and Compatibility

A peaceful and schooling fish, primarily active in the lower water layers. For comfortable well-being and to reduce stress levels, a group of 4–6 or more individuals should be kept. It coexists well with other non-aggressive fish species that are suitable in size and keeping conditions.

Care and Maintenance

For keeping a school, an aquarium of at least 100 liters is recommended. Soft sand is essential as a substrate, as sharp particles can damage the fish's sensitive barbels. The decor should include live plants, driftwood, and smooth stones to create hiding places. Lighting is preferably subdued or moderate. Quality filtration with a weak current and regular partial water changes are necessary.

Diet

An omnivorous fish, feeding in nature on worms, small crustaceans, insects, and plant detritus. In the aquarium, it accepts any specialized sinking foods for bottom-dwelling fish. The diet should be varied with high-quality dry, frozen, or live foods, such as bloodworms or Artemia.

Breeding and Reproduction

Reproduction occurs by spawning. In aquarium conditions, the process is considered challenging. Spawning is often stimulated by imitating natural changes in water parameters, such as a drop in temperature and the addition of fresh, soft water. Eggs are laid among dense vegetation or on cleaned surfaces; the fish do not exhibit parental care for their offspring.

Diseases

The species is sensitive to water purity and substrate quality. Under poor keeping conditions, damage to the barbels and the development of bacterial infections are possible. Prevention includes maintaining stable water parameters, using a soft substrate, and regular siphoning of the bottom to prevent the accumulation of organic waste.

How to choose

When purchasing, choose active fish without visible fin damage, sores, or spots on the body. It is important to ensure that the individuals have intact barbels, as their absence is a sign of improper keeping. Healthy fish should show interest in searching for food on the aquarium bottom.

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 Mosaic Corydoras get?

An adult reaches 6–8 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Mosaic Corydoras need?

The recommended volume is 100 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Mosaic Corydoras need?

Temperature 24–28 °C, pH 5.5–7.5, hardness 2–10 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Mosaic Corydoras live?

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

Is Mosaic Corydoras aggressive?

Temperament: peaceful (regular). Keep this in mind when choosing tank mates.

How many Mosaic Corydoras should be kept together?

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

What does Mosaic Corydoras 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 Mosaic Corydoras?

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

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Other scientific names and conservation status

Categories
Corydoras
Conservation status
Least concernLC