Japan Blue

Japan blue fancy guppies are Poecilia reticulata color strains with an electric metallic blue sheen, most often along the lower body, rear body, or caudal peduncle. The trait became associated with Japanese-developed fancy guppies and is also seen in Endler-influenced lines, so the name can cover several related breeding backgrounds. Japan blue is used with double-sword, top-sword, delta-tail, and patterned guppies, where the blue body color contrasts with red, orange, black, or clear fins. It is a strain name, not a separate species.

The blue flash is easiest to judge on mature males under neutral aquarium lighting, since young fish and stressed fish may look dull. Breeders working with Japan blue lines often keep careful track of which pairings produce a clean, bright body stripe and which scatter the metallic color unevenly. Because some lines include Endler ancestry or sex-linked color traits, buyers who want show stock or a closed fancy guppy line should ask how the fish were bred. Like other guppies, they are prolific livebearers and need planned space for fry.

Colors: Albino, Bicolor, Blue, Cobra, Dragon, Dumbo Ear, Endler, Grass, Green, Half-Black, Japan Blue, Koi, Leopard, Metal, Mosaic, Moscow, Multicolor, Neon Blue, Platinum, Red, Snakeskin, Solid, Tuxedo, Wild Type, Yellow