Sturisoma nigrirostrum Breeding Guide

Breeding the Black-Mouthed Whiptail (Sturisoma nigrirostrum): an open spawner laying eggs on wood/glass, with the male tending the clutch. Sexing, setup and fry care.

Overview

Sturisoma nigrirostrum, the Black-Mouthed Whiptail, is a Peruvian loricariid recorded by AquaInfo from the Ucayali River basin, where it inhabits white-water systems with current and submerged wood, reaching about 25 cm. It is an open spawner: AquaInfo reports eggs are laid on submerged wood, specifically on the underside of the wood, rather than in a cave. It is primarily herbivorous, feeding mainly on algae and plant material in nature, and AquaInfo gives a general hardness tolerance of 2-15 degrees dH.

Sexing

AquaInfo states that in the breeding season males develop a kind of beard of odontodes (denticles) on their cheeks, which females lack. Females are stouter and rounder when carrying eggs.

Conditioning

AquaInfo notes the diet, which in nature consists mainly of algae and plant material, must also be replicated in the aquarium. Condition adults on algae and vegetable foods such as blanched vegetables and algae-based tablets in clean, oxygen-rich water with good flow, providing submerged driftwood both as grazing surface and as a potential spawning site. A varied vegetable-led diet brings females into condition, after which they fill out with eggs.

Breeding Setup

Provide a mature, well-oxygenated tank with submerged wood and smooth surfaces for egg deposition and brisk current. AquaInfo gives a temperature of 24-30 degrees C (optimal breeding around 29 degrees C), pH 6.5-7.5 and general hardness 2-15 degrees dH.

Spawning Behavior & Trigger

The female lays the adhesive eggs on wood (AquaInfo: on the underside of the wood). As in the whiptail group, the male then guards and fans the clutch. Cooler, softer water changes simulating the rainy season, combined with strong flow, are the usual spawning trigger.

Egg & Fry Care

AquaInfo reports the eggs hatch after about 5 full days at 29 degrees C, with fry measuring roughly 1 cm and still carrying a yolk sac. Once free-swimming, the young consume algae from wood or are supplemented with micro worms or Artemia. Continuous access to soft food and clean water is essential.

Common Challenges

AquaInfo notes breeding is possible but the young require specific care. As with other whiptails, the main difficulties are ensuring the fry can graze continuously and maintaining strong oxygenation and current throughout incubation and rearing.