Key Features:

Distinctive Appearance: Known for its elongated “sword” extension on the lower tail fin combined with a koi-inspired Sanke pattern. It typically displays a white base body with red/orange patches and scattered black markings, giving it a bold ornamental koi-like look.

Active Swimmer: A lively and confident livebearer that is constantly on the move. Males are especially active and may display mild chasing behavior, while females tend to be calmer and more robust.

Care Requirements:

Tank Conditions: Requires a well-maintained aquarium with stable water conditions and moderate filtration. Ideal water temperature should range between 72–80°F (22–27°C). Prefers slightly alkaline to neutral water and benefits from a planted tank with open swimming space and some cover.

Diet: Omnivorous, feeding on flakes, pellets, and a variety of frozen or live foods such as bloodworms, brine shrimp, and daphnia. A balanced diet helps maintain coloration and healthy growth.

Compatibility: Generally peaceful but can show mild aggression among males or fin-nipping in crowded conditions. Best kept with other peaceful community fish of similar size. Avoid housing with overly aggressive or fin-nipping species.

Size and Growth:

Adult Size: Can grow up to 4–6 inches (10–15 cm) in length including the sword extension.

Growth: Moderate growth, with steady development and fin extension becoming more pronounced as the fish matures.

Overview:

Xiphophorus hellerii, commonly known as the Swordtail, is a popular livebearing aquarium fish, and the “Koi Sanke” variety is a selectively bred ornamental strain valued for its koi-like coloration and flowing swordtail extension. It is best suited for beginner to intermediate aquarists and thrives in stable, well-planted community aquariums with ample swimming space.