About Swordtail
The Swordtail is a striking and popular livebearer fish named for the distinctive elongated lower caudal fin ray that males develop, resembling a sword. Native to Central America, particularly Mexico, Guatemala, and Honduras, these active fish are larger than their platy cousins and bring dynamic movement to community aquariums. They display a wide variety of colors including red, green, pineapple, and neon variations. Unlike many peaceful fish, swordtails are quite energetic swimmers that utilize the entire tank. They are extremely hardy and adaptable, tolerating a wide range of water conditions, which makes them excellent choices for beginners. As livebearers, females give birth to 20-100 fully formed fry every 4-6 weeks. Males can be territorial with each other, so adequate space and hiding spots are essential. Their combination of beauty, activity, and ease of care has made swordtails aquarium favorites for decades.
Care Guide
Care Requirements
Tank Setup
Swordtails need swimming space due to their active nature. A longer tank (30+ inches) is preferred over tall tanks. Provide plants along the back and sides with open swimming lanes in the center. Use java fern, hornwort, and floating plants for cover. Include hiding spots for females and fry. Gentle to moderate filtration suits their needs. A tight-fitting lid is recommended as they can jump.
Water Quality
- Temperature: 72-82°F (22-28°C)
- pH: 7.0-8.4
- Water Hardness: Hard (10-30 dGH)
- Ammonia/Nitrite: 0 ppm
- Nitrate: <40 ppm
Very adaptable to various conditions. Regular water changes (25-30% weekly) keep them vibrant.
Feeding
Omnivorous with a preference for vegetable matter. Feed:
- High-quality vegetable-based flake food as staple
- Algae wafers or spirulina flakes
- Blanched vegetables: zucchini, cucumber, peas
- Frozen foods: bloodworms, brine shrimp, daphnia 2-3 times weekly
Feed 2-3 times daily. They are active eaters but avoid overfeeding.
Behavior & Compatibility
Peaceful but active swimmers. Males can be territorial with each other; keep only one male per 20 gallons or provide plenty of space and hiding spots. Maintain a ratio of 1 male to 2-3+ females. They may occasionally nip at long-finned tank mates. Compatible with most peaceful community fish of similar size. Use a tight-fitting lid as they are capable jumpers.
Common Health Issues
- Fin rot: Usually from poor water quality; maintain pristine conditions
- Ich: Treat with increased temperature and medication
- Swim bladder issues: From overfeeding; fast and feed peas
- Internal parasites: Quarantine new fish; treat if symptoms appear
Breeding
Easy to breed livebearers. Females store sperm and can produce multiple batches from one mating. Gestation is 4-6 weeks, producing 20-100+ fry. Fry are large enough to eat crushed flake immediately. Dense planting significantly improves fry survival. Consider separating pregnant females if you want to raise fry, or let them hide in planted tanks.
Tips for Success
- Keep only one male per 20 gallons to prevent fighting
- Maintain 2-3 females per male
- Use a tight-fitting lid; they are jumpers
- Provide ample swimming space
- Add aquarium salt (1 tbsp per 5 gallons) if keeping with other livebearers
- Breeding traps stress females; planted tanks are better for fry survival