Pygmy Corydoras

Geographic Origin and Biotope: Madeira River Basin (Peru, Brazil). Inhabits small marginal coastal rivers, flooded igapó, and stagnant zones characterized by dense root formations, submerged dead leaves (blackwater), and very thick floating vegetation.

Taxonomy and Morphology: Known as the Pygmy Corydoras (Pygmy Cory). Along with the hastatus, it is the most minute representative of the genus. The size ranges between 2 and 3 cm (0.8-1.2 inches max). Elongated and less stocky morphology compared to large corydoras, but retains the rigid scaly armor. Slightly elongated snout.

Social Behavior: Exceptionally timid and highly gregarious animal. Lives in large flocks that move in unison. Like the hastatus, it spends much of its time lifted off the bottom and swimming in mid-open waters (hovering), then resting on the large leaves of Echinodorus or Anubias.

Coloration and Sexual Dimorphism: Translucent silver-gray body. The distinguishing mark that differentiates it from the hastatus is the long uninterrupted dark horizontal stripe running along the entire flank from the snout to the tip of the tail (without the large caudal lozenge). Females are noticeably more corpulent and rounder.

Aquarium Setup: Nano tank (minimum 40 liters / 10 gallons for a school of 10). Strict requirement: soft bottom (inert sand or soft allophanic soil covered with Ketapang leaves). The aquarium must be a dense planted tank, offering myriads of plant crevices, driftwood, and floaters (Salvinia, Pistia) to shade the light.

Diet and Feeding: Insatiable micropredator with infinitesimal oral dimensions. Base diet of crumbled micro-pellets or vegetable tablets crushed in a mortar. The live or frozen intake of baby brine shrimp, microworms (Banana worms/Walter worms), and tiny daphnia is vital. Regularly grazes leaves looking for biofilm.

Water Quality: Sensitive to nitrates and the accumulation of invisible debris, given its microscopic size. Slightly acidic to neutral water (pH 6.0-7.5), soft waters (GH 2-12), and moderate temperature (22-26°C / 72-79°F). Gentle water movement (suffers from powerful pump jets).

Compatibility and Tankmates: Prized piece for peaceful "Aquascapes" or shrimp tanks (Caridina). Compatible only with "Nano" sized tankmates: Boraras brigittae, Danio margaritatus, Ember Tetras. Absolutely to be avoided with any Cichlid (even dwarfs) or Angelfish, as it would become an instant snack.

Aquarium Reproduction: Moderately easy if kept alone. Lays small sticky eggs on the underside of broad leaves or along moss filaments. Parents will ignore the eggs if adequately fed, but to survive the fry obligatorily need a mature lawn of moss rich in infusoria.

Risks and Diseases: The wear of barbels on unsuitable substrates and starvation from "too large" feeds are lethal. Suffers enormously from food competition: cannot feed if paired with fast or large bottom fish (e.g., Loaches, large Loricariids). Lethal the administration of copper or salt.