You hear about this all the time in IFGA (International Fancy Guppy Association) circles. Someone enters a guppy into competition, and it’s disqualified for the wrong color. Usually, it seems like it’s a fish in the green, blue or purple range. These photos are of the same guppy in the same 5 minute span of time. The color changes depend on the type of light and how the light is hitting the fish. This is a blue/green Moscow delta. At times it almost looks black. Other times it looks blue. Sometimes it looks blue-green. Sometimes it looks green. The variables could be fluorescent lighting, natural light, incandescent lighting, a camera flash or reflected light.
It’s also easy to see from these photos how a green Moscow might pop up in a blue line (or any number of color combinations).
Photos by Terry Aley