Berlin Swordtail

The Berlin (Red Koi) Swordtail (Xiphophorus helleri) is a stunning and colorful livebearer known for its beautiful koi-like pattern of red, white, and black markings. These attractive fish feature a white base color with patches of vibrant red and black, creating a pattern that resembles traditional koi fish. Peaceful, active, and easy to care for, Berlin Swordtails add both color variety and constant activity to any community aquarium. Their hardy nature and beautiful patterns make them perfect for both beginner and experienced aquarists.

Care Sheet – Berlin (Red Koi) Swordtail (Xiphophorus helleri)

Temperament

• Peaceful, active, and social

• Best kept in groups with mixed genders or single-sex groups

Adult Size

• Males: 4–5 inches (including sword), Females: 5–6 inches

Minimum Tank Size

• 20 gallons for a small group

Water Parameters

• Temperature: 70–82°F

• pH: 7.0–8.0 (prefers slightly alkaline water)

• Hardness: Moderate to hard (10–20 dGH)

• Ammonia/Nitrite: 0 ppm

• Nitrate: <20–30 ppm

Diet

• Omnivorous

• Feed a varied diet:

  • High-quality flakes or pellets

  • Frozen or live foods: brine shrimp, daphnia

  • Color-enhancing foods to maintain vibrant colors

• Feed small amounts 1–2 times daily

Behavior & Compatibility

• Excellent for peaceful community tanks

• Compatible with:

  • Other livebearers, larger tetras, rasboras

  • Corydoras and other peaceful bottom dwellers

  • Peaceful gouramis and rainbowfish

• Avoid aggressive or fin-nipping species

Aquarium Setup

• Planted tanks with dark substrate to enhance koi colors

• Moderate lighting to showcase patterns

• Moderate water flow

• Clean, well-maintained water

Care Level

• Easy

• Very hardy and beginner-friendly

Lifespan

• 3–5 years with proper care

Special Notes

• Beautiful koi-like pattern with red, white, and black markings

• Each fish has unique patterns - no two are identical

• Males develop sword extension with colorful patterns

• Active and colorful addition to community tanks