Hoplisoma sterbai

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Hoplisoma sterbai, also known as Corydoras sterbai, is a small South American armored catfish valued for its distinctive appearance and peaceful behavior. Native to central Brazil, it inhabits quiet, sandy areas of waterways associated with the Guaporé River basin. In an aquarium, it should be kept in a group of at least six individuals, in clean, warm, well-oxygenated water. Most active near the bottom, it searches the substrate for food and regularly interacts with its group. Its contrasting pattern, relative hardiness, and sociable temperament make it a very common and popular species among aquarium keepers.

General species description

Hoplisoma sterbai is a small armored catfish belonging to the family Callichthyidae. Like other Corydoradinae, it has two rows of bony plates protecting the flanks and barbels around the mouth that help it locate food on the bottom. It is a peaceful, shoaling fish that displays more natural behavior when maintained in a group. It often rests on the substrate with its pectoral fins and occasionally makes short trips to the surface to swallow atmospheric air. This intestinal respiration is normal in Corydoras, but it does not replace proper oxygenation. A mature, stable aquarium with open bottom areas and gentle flow is particularly well suited to this species.

Geographical origin and biotope

The distribution of Hoplisoma sterbai is associated with the Guaporé River basin in Brazil, near the Bolivian border. Its habitat includes tributaries, flooded areas, and slow-flowing sections where the water remains warm. The bottom is often made of fine sand, sometimes mixed with silt and decomposing plant material. Riparian vegetation provides shade and contributes organic matter to the water. In an aquarium, sharp gravel should be avoided because it can damage the barbels. Efficient filtration, moderate current, and regular water changes help reproduce the main conditions of this tropical environment.

Precise location and local name

Hoplisoma sterbai is mainly associated with the Guaporé River, also called the Iténez River in its Bolivian section. This region lies in western Brazil, particularly in Mato Grosso, across warm plains that are seasonally flooded. In the aquarium trade, it is commonly sold as Corydoras sterbai, Sterba’s cory, or Sterba’s corydoras. Portuguese common names can vary between regions, while international trade names are more consistent. In French, Corydoras de Sterba and cory de Sterba are clear and practical names for aquarium use.

Appearance and physical characteristics

The body of Hoplisoma sterbai is compact, low-set, and covered with bony plates. Its base color ranges from grayish brown to dark brown, with numerous pale, irregular markings across the head and body. The pectoral and pelvic fins usually show orange to yellow tones, a feature highly valued by aquarists. The dorsal fin has strong rays, while the barbels around the mouth are important for feeding. Adult females are generally larger and broader than males, especially when viewed from above. The maximum commonly reported adult size is approximately 6.5 cm.

General diet

Hoplisoma sterbai is an omnivore with a scavenging tendency that searches through the substrate, but it should not be treated as a simple cleaner fish. Its diet should include quality sinking tablets, bottom-feeding pellets, and regular frozen foods such as bloodworms, mosquito larvae, and small crustaceans. Food must reach the bottom so the Corydoras can feed properly. Offering food after the aquarium lights are partially dimmed often encourages natural activity. Sinking foods are essential, and regular variety helps maintain body condition and strong coloration.

Essential data

• Name of the original river: Guaporé River, also called the Iténez River in its Bolivian section
• Local name used: Sterba’s cory; Sterba’s corydoras
• Origin of the scientific name: Hoplisoma is used for this group of armored catfishes; sterbai honors Erwin Sterba
• Etymology of the full name: Hoplisoma comes from Greek and refers to an armed or armored body; sterbai is a dedication to Sterba
• Common/vernacular names: Corydoras sterbai, Sterba’s cory, Sterba’s corydoras
• Family: Callichthyidae
• Subfamily: Corydoradinae
• Name pronunciation: Hop-li-so-ma ster-bye
• Discovery: Hans Knaack, 1962
• Maximum adult size: About 6.5 cm
• Water temperature and pH: 24 to 28 °C; pH 6.0 to 7.5
• Waterway appearance and surrounding vegetation: Warm, slow to moderate-flowing water, sandy bottom, plant debris, and shaded riparian vegetation
• Typical tankmates: Small peaceful tetras, small characins, peaceful Apistogramma, small loricariids, hatchetfish, and other compatible Corydoras
• Temperament and behavior: Peaceful, social, shoaling, and active near the bottom
• Water depth: Shallow to moderately deep sections of tributaries and flooded areas
• Sexual dimorphism: Females are larger and broader; males are usually smaller and more slender
• Bottom structure and flow: Fine sand or silt, plant debris, and low to moderate current

In your aquarium

Keeping Hoplisoma sterbai successfully begins with a mature aquarium offering open bottom space, a soft substrate, and several shelters. Keep it in a group, provide sinking foods, and avoid aggressive or oversized tankmates. Stable, warm, well-oxygenated water is more important than maintaining one exact pH value. Regular water changes, clean bottom areas, and filtration without excessive current will help protect the barbels and maintain vitality. With these straightforward conditions, this corydoras remains an excellent choice for a peaceful community aquarium.