L034, Medusa Pleco

Geographic Origin and Biotope: Tocantins and Xingu river basin and related tributaries in Brazil. Typically found wedged under large formations of flat rocks in the strong flow of the "rapids" or along the stony coasts of these enormous clearwater basins.

Taxonomy and Morphology: Medusa Pleco (L034 / Ancistrus ranunculus). Exceptionally wide shape, flattened like a "sole" to resist the most extreme turbulence. The nickname "Medusa" derives from the monstrous tangle of tentacles arranged radially on the head, similar to the mythological being.

Social Behavior: Peculiarly gregarious in youth, it becomes intolerant of members of the same species when it reaches maturity. Of an "engineering" nature: it will spend whole nights moving sand and gravel from under the stones to create impenetrable caves.

Coloration and Sexual Dimorphism: Solid opaque black or anthracite background, without any spotting or striping. Adult males are stunning: the tentacles (bristles) develop immensely creating a huge tangle on the snout and up to the eyes, much denser than normal Ancistrus.

Aquarium Setup: Minimum 120 cm (48 inches) tank with a rocky "River" layout. Stack slate slabs guaranteeing stable crevice hiding places (horizontal caves). Powerhead pump is mandatory to recreate the fast currents of the Xingu river. Useless plants (uproots them smoothly).

Diet and Feeding: Predominantly Omnivorous-Carnivorous, unlike the average Ancistrus. Often rejects pure plant diets. It should be fed with frozen bloodworms, mysis, crumbled shrimp and protein flakes that fall near its den at night.

Water Quality: Heat and oxygen are the golden parameters: high temperatures (26-29°C / 79-84°F) with massive surface aeration to prevent asphyxia in warm waters. Keep nitrates close to zero to avoid infections to the fragile tentacles.

Compatibility and Tankmates: Ideal companion for Geophagus, large Tetras (Columbian tetra, Bleeding Heart) and large Corydoras, as they occupy different niches. Keep only one male per tank (unless aquariums of over 2 meters / 6.5 feet) to prevent lethal positional wars.

Aquarium Reproduction: Complex. Requires caves with an entrance just sufficient for it to pass through, inserted perpendicularly to the current. The brooding lasts almost two weeks: the father fans vigorously without ever coming out. Cannibalism on the eggs is common in case of stress.

Risks and Diseases: In case of territorial fights between males, or prolonged water stress, the very black epidermis will irregularly become pale-spotted before resulting in a severe external mycosis. Fatal entrapment in nets.