Twig Catfish (Farlowella acus) Breeding Guide

Breeding the Twig Catfish (Farlowella acus): sexing by snout odontodes, eggs laid on a vertical surface, male egg-guarding and fanning, and very demanding fry rearing.

Overview

Farlowella acus is a slender, herbivorous loricariid catfish from South America that requires stable, well-oxygenated water. It is an egg layer in which the male guards the eggs, and the fry are notoriously difficult to raise because they are prone to starvation.

Sexing

Males develop a broader snout, and as they mature the rostrum becomes covered in rows of small bristles called odontodes; the females' thinner snouts remain smooth at all times.

Conditioning

Because the species is strongly herbivorous, achieving proper nutritional balance is challenging; condition the fish on algae and vegetable-based foods. Naturally, spawning occurs between November and March, but well-conditioned captive fish can be induced to breed at any time.

Breeding Setup

Provide hard vertical surfaces, very often the aquarium glass, where the male can clean a site for egg deposition. Starting with a group of six or more juveniles helps secure a compatible pair.

Spawning Behavior & Trigger

The male cleans a hard surface and the female lays her eggs there at night or in the early morning, almost always on a vertical surface. The female normally lays a clutch of about 60 to 80 eggs, and the male may be visited by additional females who add their eggs to the existing brood.

Egg & Fry Care

The male tends the eggs with his mouth and by fanning them with his pectoral fins until they hatch in around six to ten days, depending on temperature. Newly hatched young attach to surfaces near where they hatched and absorb a small yolk sac within days, after which they need constant access to soft vegetable matter such as pre-softened kale and spinach, plus algae grown on rocks.

Common Challenges

The fry are particularly susceptible to starvation and are notoriously difficult to raise, so providing a steady supply of suitable soft vegetable food and maintaining stable water are the central difficulties.