Hoplo Catfish

Geographic Origin and Biotope: Ubiquitous in South America (Amazon, Orinoco and Paraguay basins). Lives in almost every imaginable habitat, from stagnant swamps suffocated by vegetation to large clear rivers. Excels in survival in drying and hypoxic pools.

Taxonomy and Morphology: Formerly Hoplosternum thoracatum, renamed Megalechis. "Spotted Hoplo". Size of 15 cm (6 inches). Stocky body massively armored by overlapping bony shields, adapted for accessory aerial respiration through modified intestinal walls.

Social Behavior: Extremely sociable and fearless. Tireless explorer (mainly crepuscular), constantly rummages the bottom with unparalleled enthusiasm. Ignores conspecifics if the tank is large, preferring to rest piled up on trunks and rocks during the day.

Coloration and Sexual Dimorphism: "Spotted" camouflage pattern: dark brown to grayish background heavily and irregularly dotted with black. The male in reproductive phase unleashes a purplish belly and a monstrous front pectoral spine (ossified) colored copper to defend the nest.

Aquarium Setup: Watertight tank to prevent escapes. Prefers a bed of soft sand or mud (never sharp gravel that mutilates its barbels), abundant intertwined roots and an uncovered water surface for the periodic breath of vital air.

Diet and Feeding: Highly voracious opportunistic omnivore. Cleans the tank of any leftovers. Feed abundantly with industrial catfish pellets, huge earthworms, insects and spirulina tablets. Munches on small excess snails.

Water Quality: Stunning chemical tolerance. Effortlessly resists thermal shocks (20-28°C / 68-82°F), acidic or basic pH (5.5 - 7.5) and high hardness (GH up to 20). However, the high organic load it produces requires massive siphonings so as not to intoxicate it.

Compatibility and Tankmates: Mild colossus for large South American tanks. Ideal with Oscars, Acaras, Geophagus and large Tetras. Eats anything that enters its mouth, forbidden insertion with small Tetras, Rasboras or tiny Corydoras which will inevitably be swallowed at night.

Aquarium Reproduction: Anomalous breeder: the male builds a powerful nest of bubbles and leaves on the surface (under large water lilies). After spawning, the male becomes a rabid and lethal guardian: attacking any intruder, forces the breeder to remove the female.

Risks and Diseases: Almost indestructible armored fish, but at risk of fatal injuries to the barbels if housed on volcanic or sharp bottoms. Enormous vulnerability, like many "scaleless" fish, to pharmacological treatments based on Malachite Green.