Glassbelly Yellow Guppy (GBY)
The Glassbelly Yellow Guppy is a fascinating example of how specific genetic traits can transform a standard ornamental fish into a living “X-ray.” This strain is highly prized in the Singapore hobby for its unique transparency and striking contrast.
The Glassbelly Trait
The “Glassbelly” (GB) characteristic is a recessive mutation that suppresses the development of iridophores (silvery reflective pigments) and leucophores (white pigments) in the abdominal area.
Unlike many other translucent strains, the GBY maintains a vivid, solid yellow pigmentation across its body and fins, while the “window” to its internal organs remains clear.
Key Characteristics
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Internal Visibility: The most iconic feature of this strain is the ability to view the female’s internal organs. During pregnancy, you can clearly observe the development of the fry. As the birth date approaches, the individual black eyes of the babies become visible through the mother’s belly.
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Solid Black Eyes: While many yellow guppy strains are Albinos (RREA) with red eyes, the true Glassbelly Yellow features deep, full black eyes. This provides a sharp, aesthetic “pop” against the bright yellow body.
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Breeding Precision: For breeders, the Glassbelly trait removes the guesswork. You can monitor the exact stage of fry development, making it much easier to time the move to a maternity tank or breeding trap.
Visual Showcase: Glassbelly Yellow in Motion
In the video above, notice the transparency of the females and the distinct black eyes of the fry visible in the gravid spot area. Even with the transparent belly, the yellow saturation remains high.
Quick Care & Breeding Tips
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Water Clarity: To truly appreciate the Glassbelly trait, pristine water clarity is essential. We recommend a consistent water change schedule and the use of fine mechanical filtration to keep the “view” sharp.
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Background Choice: Use a dark background (black or deep blue) in your tank. This makes the yellow pigment glow and emphasizes the transparency of the mid-section.
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Genetics Note: Since the Glassbelly gene is recessive, breeding a Glassbelly to a non-Glassbelly will result in “normal” looking fry that carry the gene (heterozygous). To maintain the look, you must breed GB to GB or backcross to a carrier.