Velvet Red Swordtail Breeding Guide

Breeding the Velvet Red Swordtail (Xiphophorus hellerii), a deep-red livebearer, with sexing, 24-30 day gestation, large broods, fry care and late-male notes.

Overview

The Velvet Red Swordtail is a solid deep-red strain of Xiphophorus hellerii (family Poeciliidae), a livebearer with internal fertilisation. Most aquarium swordtails are hybrids to some degree because the species crossbreeds with the platy X. maculatus. Wild swordtails inhabit rapidly flowing, heavily vegetated streams from Veracruz, Mexico to northwestern Honduras and grow larger than guppies or platies, needing a bigger tank.

Sexing

Males develop a gonopodium and the characteristic caudal sword, which females lack. Some are late-maturing males whose sword appears later than usual, and the species can undergo female-to-male sex reversal under certain environmental conditions.

Conditioning

An omnivore feeding on worms, crustaceans, insects and plant matter, the swordtail conditions on a varied diet in stable, slightly hard alkaline water (the species occurs across roughly 22-28 C and pH 7.0-8.0). Carotenoid-rich foods support the red colour.

Breeding Setup

Both sexes present breed readily. A ratio of one male to three or four females limits harassment, since males are aggressive toward each other. A well-developed male spurs female maturity while inhibiting juvenile-male maturity. Provide plants for fry refuge.

Mating & Gestation

Males fertilise females internally via the gonopodium, and females store viable sperm for extended periods. A dark gravid spot develops near the anal fin in late pregnancy. Gestation lasts about 24 to 30 days, with sexual maturity at roughly eight to twelve months.

Birth & Fry Care

A female produces 20 to 200 live young per brood. Dense plants let fry hide from adults. Fry take powdered and small live foods and grow steadily; the deepest red typically develops with age and good nutrition.

Common Challenges

Male aggression makes a balanced sex ratio important, and platy hybridisation in the trade dilutes pure swordtail lines. Holding the solid red colour true requires selecting the most intensely coloured parents; late-developing males may be mistaken for females until the sword forms.