Description
Koi Swordtail (Xiphophorus helleri)
📌 Basic Info
Scientific Name: Xiphophorus helleri
Common Names: Koi Swordtail, Tricolor Swordtail, Marble Swordtail
Family: Poeciliidae
Order: Cyprinodontiformes
Origin: Central America — primarily from rivers and streams in Mexico, Belize, and Honduras (now captive-bred globally)
Size: 10 – 12 cm (4 – 5 inches) including tail extension
Lifespan: 3 – 5 years
Tank Zone: Middle and upper levels
🌊 Water Parameters
Temperature: 22 – 28°C (72 – 82°F)
pH: 7.0 – 8.2
Hardness: 10 – 30 dGH
TDS: 200 – 400 ppm
🐠 Characteristics
Body Shape: Slender and elongated body with a signature sword-like tail in males.
Coloration: Striking mix of white, orange, and black patches, resembling the colors of a koi carp.
Tail: Males develop a long sword-shaped extension from the lower lobe of the tail fin.
Behavior: Active, peaceful, and social community fish.
Special Feature: The unique koi-like tricolor pattern makes each fish visually distinct — no two look exactly alike.
🍽️ Diet
Type: Omnivorous
Diet: Quality flakes, micro pellets, daphnia, brine shrimp, and spirulina-based foods.
Feeding Frequency: 1–2 times daily in small portions.
Tip: Feed color-enhancing foods for brighter red and orange tones.
🛠️ Tank Maintenance
Tank Size: Minimum 80 liters (20 gallons) for a small group
Filtration: Moderate to strong flow with efficient biological filtration
Substrate: Fine gravel or sand
Decor: Provide plants like Vallisneria, Anubias, and Hornwort with open swimming areas
Lighting: Moderate lighting to highlight color contrast
Water Change: 25–30% weekly
👥 Social Behavior
Nature: Peaceful and lively livebearer
Group Size: Keep one male for every 2–3 females
Tank Mates: Guppies, Mollies, Platies, Corydoras, Tetras, and Rasboras
Avoid: Aggressive fish or fin nippers
Breeding: Livebearer; females give birth to fry every 4–6 weeks. Use dense plants or breeding boxes to protect fry.
✅ Do’s
• Maintain clean, oxygen-rich water
• Provide plants for shelter and fry protection
• Offer a balanced diet with color foods
❌ Don’ts
• Avoid overstocking or multiple males in a small tank
• Don’t mix with aggressive species
• Avoid dirty or fluctuating water parameters
⭐ Quick Tip:
The Koi Swordtail is a vibrant tricolor livebearer known for its striking orange, black, and white pattern — much like koi fish. It’s hardy, peaceful, and perfect for brightening up any freshwater aquarium.




