Spotted Medusa Pleco L104

Ancistrus sp. L104, the Spotted Medusa Pleco, is one of the most unusual-looking loricariids available in the aquarium hobby. Its most striking feature is the dramatically elongated snout adorned with elaborate, branch-like sensory growths resembling medusa tentacles, used to detect food in the low-visibility blackwater environment. The body is compact and dark, scattered with pale spots that stand out against the background.

This species originates from the dim, tannin-stained blackwater rivers of the Rio Negro basin in Brazil, where soft, extremely acidic water prevails. Replicating these conditions — pH 4.5–6.5, very soft water, warm temperatures — is essential for long-term health and willingness to breed. Driftwood, leaf litter, and dark substrate complete the biotope setup.

The Spotted Medusa Pleco is an omnivore that accepts a range of sinking foods including high-protein pellets, bloodworms, and algae wafers. Males are territorial toward each other and should each have their own cave. It is a moderately challenging species primarily due to its strict blackwater water chemistry requirements.

Water: 26–30°C, pH 4.5–6.5, very soft blackwater; avoid hard or alkaline conditions at all costs. Tank: Minimum 100 L; driftwood, leaf litter, clay caves, dark substrate, subdued lighting. Feeding: Omnivore; bloodworms, brine shrimp, high-protein pellets, algae wafers, Repashy. Breeding: Cave spawner; male guards clutch; blackwater conditions and stable temperature essential for success. Compatibility: Peaceful with other blackwater community fish; males territorial toward each other.