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Halfmoon Guppy
Poecilia reticulata
Animalia›Chordata›Actinopterygii
Variety of Guppy · halfmoon
📍 South America
The Halfmoon Guppy has a large, fan-shaped tail that spreads to nearly 180°, similar to the halfmoon betta tail shape. Selective breeding for this trait requires careful husbandry to maintain fin integrity.
Care Guide
Diet
Halfmoon Guppies are omnivorous and thrive on high-quality flake foods, micro pellets, and small frozen foods like brine shrimp and daphnia once daily. Supplement with vegetable matter such as blanched spinach or algae-based foods weekly to support coloration and fin development. Feed small amounts multiple times per day rather than one large feeding to maintain water quality.
Behavior
Halfmoon Guppies are peaceful, active swimmers that spend most of their time in mid-water levels exploring their environment. Males display elaborate courtship behaviors with their large fan-shaped tails, while females are less colorful and more reserved. They are social fish that do well in groups, though males may show mild aggression toward each other; provide adequate space and visual barriers to reduce tension.
Breeding
Halfmoon Guppies breed readily in captivity and are livebearers, making them excellent for beginners interested in breeding. Females produce 20-40 fry every 4-6 weeks when kept with males; separate pregnant females into a breeding tank with dense plants to protect fry from predation. Maintaining selective breeding for the halfmoon tail shape requires culling inferior specimens and careful line management over multiple generations.
Tank Mates
Same family, compatible water parameters, and peaceful temperament; may hybridize if both sexes present
Similar size and water requirements; peaceful community fish that won't nip delicate guppy fins
Peaceful mid-water swimmer with compatible temperature range; monitor for any territorial behavior
Algae eater that helps maintain tank cleanliness without competing for food or space
Common Diseases
Fin Rot
Fraying, discoloration, or deterioration of tail and fin edges; particularly problematic in halfmoon varieties with large fins
Perform 25% water changes every 2-3 days, maintain pristine water quality, and treat with aquarium salt (1 teaspoon per 5 gallons) or antibacterial medication if severe
Ich (Ichthyophthirius multifiliis)
White spots on body and fins, rapid gill movement, lethargy, and rubbing against objects
Raise water temperature to 28-30°C gradually, treat with ich medication following package directions, and perform daily water changes; maintain treatment for 10-14 days
Velvet Disease (Oodinium)
Fine golden or rust-colored dust on body, clamped fins, rapid breathing, and loss of appetite
Increase aeration, treat with copper-based medication or salt baths, and dim lighting as the parasite is light-sensitive; quarantine affected fish
Popeye (Exophthalmia)
One or both eyes bulging outward, cloudiness, and potential eye loss if untreated
Perform immediate 50% water change to improve water quality, treat with antibacterial medication, and investigate water parameters for ammonia or nitrite spikes
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Varieties
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