Breeding the swordtail
Livebearer; females can store sperm for months. Matures at 8-12 months; females sometimes change sex to male.
Step by step
Buy 1 male and 2-3 females.
60 L tank with plants and a sponge filter. Give them space.
No trigger needed; females give birth about every month.
20-200 young per brood after 24-30 days gestation.
Fry are born ready to eat. Feed crushed flake, baby brine shrimp and microworms several times a day. Separate fry from adults or use plants as cover. Sort by size and sex early.
- Overcrowding
- Aggressive males
- Leaving fry with adults
Male or female
Males have a 'sword' (extended lower tail-fin lobe) and a gonopodium; females lack both and grow larger. Some ornamental strains have extended fins in females too.
Can I breed it in my tank?
- Good for a first breeding project.
Day-by-day plan
Typical for livebearers
- 28 days beforePregnancy
A dark 'gravid spot' grows behind the belly. Gestation is usually about 4 weeks.
- Day 0Birth
Fry are born ready to swim. Thick plants or a breeding box keep them safe from adults.
- Day 0First food
Feed crushed flake, baby brine shrimp or microworms 3–5 times a day.
- Day 28Sexing starts
Males start to show color and a pointed anal fin. Separate them if you want to control lines.
- Day 90Adults
Most livebearers are grown and can breed at about 3 months.
A general guide for this breeding type. Days change with temperature and species.
Simulator: guided
A dark 'gravid spot' grows behind the belly. Gestation is usually about 4 weeks.
Simulator: try it yourself
Set up a virtual breeding tank and see what would likely happen.
- The female gave birth.
- With no plants or breeding box, the adults ate most of the fry.
An educational estimate from the breeding rules, not a promise.