Guppy Cobra Blue

The Cobra Blue Guppy is a fancy strain of Poecilia reticulata, the common guppy, selectively bred to display a distinctive 'cobra' or reticulated pattern of dark irregular markings over a vivid blue base color, particularly on the posterior body and caudal peduncle. The tail fin is large, often a veil, fan, or delta shape, matching the blue and dark cobraskin pattern of the body. Females are larger, plainer, and silvery-gray with a gravid spot near the tail when pregnant.

Poecilia reticulata is native to the fresh and brackish waters of Trinidad, Venezuela, Barbados, and surrounding Caribbean regions, but has been introduced worldwide. The wild fish is a small, dull-colored fish — all the brilliant varieties seen in the hobby are products of over a century of selective breeding. Fancy guppies are among the most genetically variable domesticated fish, with hundreds of recognized strains.

Cobra Blue Guppies are peaceful, active livebearers that adapt readily to a range of conditions. They are highly prolific — females give birth to live fry without any intervention from the keeper. In a planted aquarium, the species will multiply rapidly if mixed-sex groups are kept. They are excellent fish for beginners learning about livebearer biology and genetics.

Tank Setup A minimum 40-liter tank for a small group. Use fine-leaved or dense plants — Java Moss, Hornwort, Water Sprite — to provide fry cover if breeding is desired. Gentle HOB or sponge filter. Heater set to 22–28°C. Cover the filter intake with a pre-filter sponge to prevent fry loss. A secure but breathable lid.

Water Parameters Maintain pH 6.5–8.5, temperature 22–28°C. Adaptable to a wide range of water hardness. Prefer slightly hard, neutral to alkaline water. Weekly 25–30% water changes. Tolerant of moderate variation, making them truly beginner-accessible.

Feeding Omnivorous. Accept flake food, micro pellets, frozen baby brine shrimp, daphnia, and spirulina flakes. A varied diet significantly improves male color vibrancy. Feed small amounts two to three times daily.

Reproduction Highly prolific. Females can give birth to 20–60 fry every 4–6 weeks. Population can increase rapidly — plan for fry management. Keep sex ratios at 1 male to 2–3 females to reduce female stress from male harassment.

Male-to-Female Ratio Always keep more females than males. Single males harass females relentlessly. Ratios of 1:2 or 1:3 (male:female) are ideal.

Tankmates Compatible with most small, peaceful community fish: tetras, corydoras, small loaches, and other livebearers. Avoid fin-nipping species that target the flowing tail fin, and large fish that may eat them.

Health Notes Generally very hardy. Susceptible to velvet (Oodinium) when stressed or in suboptimal conditions. Wasting disease in long-inbred lines. Source quality stock from reputable breeders.

Long-term Notes Fancy guppies are short-lived compared to many aquarium fish, typically 1.5–2.5 years in the hobby. Population renewal through controlled breeding is the primary long-term strategy for guppy keepers. Maintaining a quality broodstock pair or small breeding group separate from the display tank allows selective preservation of desired traits across generations. Maintain consistent water changes and monitor for population explosion in mixed-sex groups — in a small tank, overpopulation can quickly deteriorate water quality and stress all inhabitants including the adult fish.