Armored Catfish (Callichthyidae)

Bloch's Corydoras

Corydoras blochi

The fish, scientifically known as Corydoras blochi, belongs to the armored catfish family (Callichthyidae). Its natural range covers many river systems in South America, including the vast Amazon River basin. Bloch's Corydoras is easily found in the waters of Venezuela, Guyana, and the northern regions of Brazil, from where it originates.

Tank
from 70 L (18 gal)
Temperature
20 – 25 °C (68 – 77 °F)
Size in aquarium
5 cm (2 in)
Acidity
pH 6–8
Natural rangeRange on the map
  • Amazon River Basin
  • Northern Brazil area
  • Brazil
  • Guyana
  • Venezuela

Tank conditions

Plan the tank stocking
Temperature
20 – 25 °C (68 – 77 °F)
Water pH
Slightly acidic (6) – Slightly alkaline (8)
Water dH
Very soft (2) – Very hard (25)
Water salinity
no salt (freshwater)
Size in aquarium
5 cm (2 in)
Lifespan
6 years
Temperament
Peaceful (regular)
Toward small fish
not a predator
Required aquarium volume
from 70 L (18 gal)
Lighting
dimmed
Substrate
soft silted
Water flow
weak or moderate
Swimming level
near the bottom
Feeding
Sinking (any)
Keeping
Small group 3–4 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 (3–4 individuals)), footprint, decor and tank mates.

Care and keeping

Description

Adult specimens of this catfish typically reach a length of about 5 cm. In terms of its morphological characteristics, it is quite similar to most other Corydoras species. The fish's body appears robust and stocky, protected by rows of bony plates. Notably, the first rays of its fins have transformed into distinctive spines. Such powerful protection makes it virtually invulnerable to attacks from small predators. Bloch's Corydoras usually has a light coloration, with a characteristic pattern of black rounded spots. A distinctive feature is a dark pigmentation spot at the base of the dorsal fin.

Habitat

The species' range includes river systems in South America, including the Amazon River basin, as well as the waters of Venezuela, Guyana, and the northern states of Brazil. The fish prefer the bottom layers of water in rivers with slow to moderate currents. In nature, they inhabit soft, slightly acidic water, but the species demonstrates high adaptability to various keeping conditions.

Behavior and Compatibility

Like many members of its genus, this catfish exhibits a peaceful and calm disposition. It thrives in the company of its own kind and also shows excellent compatibility with other non-aggressive species that are comparable in size and temperament.

Care and Maintenance

For a small group of six fish, an aquarium of 70 liters or more will suffice. When setting up the tank, it is important to create plenty of hiding places and to provide areas with soft sandy substrate, which the catfish enjoy digging in. Hiding places can include both artificial decor and natural elements: pre-treated driftwood, dense thickets of aquatic plants, or certain tree leaves. Wild specimens prefer soft, slightly acidic water, but acclimated fish adapt quite successfully to higher pH and dGH values. These catfish have a reputation for being undemanding and relatively easy to keep. Regular aquarium maintenance combined with a quality filtration system will help maintain water at an appropriate level.

Diet

In their natural environment, catfish feed on small invertebrates and organic detritus. In aquarium conditions, they accept any high-quality sinking foods, including specialized tablets, granules, and flakes for bottom-dwelling fish. To maintain health and prepare for breeding, it is recommended to supplement their diet with live or frozen foods: bloodworms, daphnia, tubifex, or enchytraeids.

Breeding and Reproduction

Spawning is paired. The female holds the eggs between her ventral fins, where fertilization by the male's milt occurs, after which she transfers the eggs to a substrate, usually among dense plant thickets. This process is repeated multiple times until the clutch is complete, which can number up to 100 eggs. The incubation period is 3–4 days. There is no parental care for the offspring.

Diseases

The species has a strong immune system when kept in proper conditions. The main danger comes from bacterial infections arising from poor water quality and substrate contamination. An important preventive measure is the use of fine, soft sand, as sharp gravel particles can injure their sensitive barbels, opening the way for fungal and bacterial infections.

How to choose

When selecting individuals, pay attention to the fish's activity: healthy catfish constantly explore the bottom in search of food. Barbels should be intact, without signs of erosion or damage. The fish's body should be clean, without film, spots, or ulcers. Avoid purchasing individuals that appear emaciated, lethargic, or stay near the water surface, as this may indicate health problems or unsatisfactory conditions in the store's aquarium.

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 Bloch's Corydoras get?

An adult reaches 5 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Bloch's Corydoras need?

The recommended volume is 70 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Bloch's Corydoras need?

Temperature 20–25 °C, pH 6–8, hardness 2–25 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Bloch's Corydoras live?

Around 6 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Bloch's Corydoras aggressive?

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

How many Bloch's Corydoras should be kept together?

Recommended setup: small group (3–4 individuals). Ignoring this is a common cause of stress and disease.

What does Bloch's 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 Bloch's Corydoras?

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

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Other scientific names and conservation status

Categories
Corydoras
Conservation status
Least concernLC