Lionhead Goldfish Breeding Guide

How to breed the lionhead goldfish (Carassius auratus): sexing by tubercles, spring temperature trigger, adhesive scattered eggs, hatching and selective culling.

Overview

The lionhead is a fancy variety of the goldfish, Carassius auratus, and shares the same reproductive biology as all goldfish. It is an egg-scattering, oviparous spawner whose eggs are sticky and become attached to water plants or submerged objects. Females spawn several batches of eggs across the breeding season rather than a single clutch.

Sexing

Sexes are not reliably distinguishable outside the breeding period. As the season approaches, males develop breeding tubercles (white pinhead-sized spots, also called breeding stars) on the gill covers, head and sometimes the leading rays of the pectoral fins. Females in spawning condition become noticeably rounder as they fill with eggs.

Conditioning

Goldfish reach spawning condition only with adequate space and good nutrition. Cool water temperatures over winter are necessary for proper development of the ova, so a seasonal temperature cycle helps prepare breeders. Condition adults on a varied diet before the intended spawning period.

Breeding Setup

Provide a spawning medium for the adhesive eggs to attach to, such as dense fine-leaved plants like Cabomba or Elodea, or an artificial spawning mop. Because the eggs cannot be moved once laid, the breeding container should already hold the spawning medium before chasing begins.

Spawning Behavior & Trigger

Spawning usually follows a significant rise in temperature, typically in spring. With temperatures around 20-23 degrees C (68-73 degrees F) males begin chasing gravid females, persisting from dawn until early afternoon, bumping and nudging them to release eggs. The sticky eggs scatter onto the plants or mop and are fertilised by the pursuing males.

Egg & Fry Care

Remove the parents as soon as spawning is over, because goldfish readily eat their own adhesive eggs, which cannot be relocated. Eggs hatch in roughly 48 to 72 hours (about four days), and fry become free-swimming around 24 hours later, at which point feeding begins with newly hatched brine shrimp or a fine fry food. Within a week or so the fry start to assume their final shape, though they remain a metallic brown like wild ancestors and may take a year to develop mature coloration.

Common Challenges

Lionheads are a selectively bred variety, so fry must be graded and culled to maintain the dorsal-less back profile and the characteristic head growth (wen); only a fraction of any spawn shows the desired form. Some heavily modified fancy goldfish can no longer spawn naturally because of their altered body shape, and hand-stripping is sometimes used, although it can injure the fish if done incorrectly.