Breeding Ancistrus ranunculus (L034)

How to breed the L034 medusa pleco Ancistrus ranunculus: sexing by tentacles, a soft acidic cave setup, male brood care and raising the large orange-egg fry.

Overview

Ancistrus ranunculus, known in the hobby as the medusa pleco or L034, is a loricariid catfish native to the Xingu, Trombetas and Tocantins river basins in Brazil, where it inhabits narrow cracks in submerged rocks and spaces below flat rocks. According to Seriously Fish it is a cave spawner that requires a dedicated spawning setup. Wikipedia lists it as Near Threatened on the IUCN Red List.

Sexing

Only males develop the full, bushy growth of tentacles covering the head, and males also possess cheek odontodes (spines on either side of the head). These features make mature males straightforward to distinguish from females.

Conditioning

Condition the breeding fish with plenty of live and frozen foods prior to spawning to bring females into condition.

Breeding Setup

Seriously Fish recommends soft, acidic, very well-oxygenated and turbulent water for spawning, at a temperature of 80-84 F (about 27-29 C) and pH 6.0-6.5. No substrate is required, and caves are provided as spawning sites.

Spawning Behavior & Trigger

Males establish and vigorously defend territories and entice females into a cave. A successful male is briefly ejected from his cave while the female goes inside to lay her eggs, after which the male assumes sole responsibility for defending the cave against intruders.

Egg & Fry Care

The eggs are large and orange and hatch in 4-5 days, with the male providing all parental care. Fry remain in the cave under his protection until their yolk sacs deplete. Once feeding, the fry require heavy feedings of greenstuffs such as blanched spinach, cucumber slices and algae wafers, plus small invertebrates such as microworm and brine shrimp nauplii; food should be available at all times. Seriously Fish reports broods of at least 40-50 fry.

Common Challenges

The species demands clean, highly oxygenated water with strong movement, mirroring its fast-flowing natural habitat, so water quality must be maintained throughout the brood-care period. Heavy fry feeding makes diligent maintenance essential to avoid fouling the tank.