Live Fish Japanese Blue Tail

The Japanese Blue Tail Guppy (Poecilia reticulata) is a premium, selectively bred freshwater ornamental fish highly prized for its vibrant metallic body and striking blue tail fin. Originally developed through careful genetic selection in Japan, this hardy, peaceful, and energetic livebearer is a favorite for both beginner aquarists and veteran guppy breeders.

Key Features & Physical Description

• Vivid Coloration: Features a distinctive shimmering, metallic "Japan Blue" body that transitions into a contrasting, graceful blue tail. Depending on the sub-strain (such as Blue Grass or Mosaic), the tail can range from solid electric blue to intricate speckled or patterned designs. 
• Sexual Dimorphism: Males are smaller, usually measuring 1.5 to 2 inches, but they boast intense blue shades and elaborate, flowing fins. Females are larger (up to 2.5 inches) with a more rounded body shape and display much lighter, subdued color tones. 
• Tail Variations: While most commonly found with a broad delta or fan tail, specific regional breeding lines also include distinct variations like the Japanese Blue Swordtail. 

Key Characteristics 

• Genetic Background: Developed in Japan through selective breeding. The "Japan Blue" gene is located on the Y-chromosome. This means fathers pass the distinct metallic blue body color directly to their male offspring.
• Size: Males are smaller and sleeker, reaching 3.5 to 5 cm (1.5 to 2 inches). Females are noticeably larger and rounder, growing up to 6 cm (2.5 inches).
• Coloration: Males display a striking dual-tone look. Their bodies shine with a metallic, silvery-blue sheen, which stands out against their vivid, deep blue tail and dorsal fins. Females are mostly gray or silver, showing only faint hints of blue on their tails.
• Fin Shape: Features a prominent, flowing delta or fan-shaped tail. They also have an elongated dorsal fin that drapes elegantly over the back half of their body.
• Reproduction: Classified as ovoviviparous livebearers. Instead of laying eggs, females fertilise eggs internally and give birth to fully formed, free-swimming fry after a 21 to 30 day gestation period.
• Activity Level: Highly energetic and fast-moving swimmers. They spend most of their time actively exploring the top and middle layers of the water column.
• Lifespan: Average lifespan ranges from 2 to 3 years when kept in stable water conditions and fed a balanced diet.