Blue Moscow Guppy Care Guide - Aquarium Tips, Feeding & Breeding

Blue Moscow Guppies are a striking fancy guppy variety known for their rich, deep blue coloration. The blue pigment can cover much of the body and extend into the fins, producing a metallic or almost midnight-blue appearance, particularly in mature males. Individual fish vary in shade, pattern and fin shape because the name describes a cultivated strain rather than a single fixed body pattern.

Like other guppies, they are active, alert and constantly exploring the aquarium. Males often display to females and to one another by spreading their colourful tails and flicking their bodies, but serious aggression is uncommon in a well-managed group. Their small size and lively personality make them popular community fish.

Wild guppies come from a wide range of habitats, including shallow streams, drainage channels, pools and slow-moving margins with vegetation. This adaptability has helped the species become established in many regions outside its original range, although introduced populations can affect native ecosystems.

Blue Moscow Guppies are selectively bred aquarium fish and may show larger tails, fuller fins and more intense colour than wild-type guppies. Their appearance is best appreciated in a planted aquarium where their dark blue bodies contrast with green foliage and a light or natural-coloured background.

Poecilia reticulata is native to northern South America, including Venezuela, Guyana, Suriname and parts of Brazil, as well as several Caribbean islands such as Trinidad and Barbados. Blue Moscow is a selectively bred ornamental strain rather than a naturally occurring wild colour form.

A group of six Blue Moscow Guppies should have at least a 60-litre aquarium, with a footprint of around 60 × 30 cm or larger; a longer tank is preferable because it provides useful swimming space. Use gentle to moderate filtration with a secured intake, as fancy guppy fins can be damaged by strong currents. Include open areas for swimming, dense live plants, floating cover and some wood or smooth rocks, with fine gravel or sand as a suitable substrate. A tightly fitted lid is advisable because guppies can jump, and stable, well-filtered freshwater is more important than elaborate decoration.

Males usually reach about 3 cm (1.2 inches), while females can grow to approximately 6 cm (2.4 inches). Selectively bred fancy strains may differ slightly in final size, and the flowing tail can make males appear larger than their body length suggests.

Blue Moscow Guppies are omnivores and do best on a varied diet. Offer a quality small-pellet or flake food as the staple, supplemented with finely chopped frozen or live foods such as baby brine shrimp, daphnia and mosquito larvae. Blanched spinach, spirulina-based foods or other vegetable-rich foods can provide useful plant matter. Feed small portions once or twice daily, giving only what they consume promptly, and use appropriately tiny foods for fry.

Blue Moscow Guppies can live with peaceful, similarly sized community fish such as platies, mollies, small rasboras, neon tetras, ember tetras, peaceful Corydoras and small non-aggressive bristlenose catfish. Avoid fin-nipping species such as tiger barbs, larger serpae tetras and some danios, along with aggressive cichlids and fish large enough to eat them. Long-finned males may be vulnerable to persistent nipping, and keeping males with too few females can lead to excessive harassment. Remember that mixed-sex groups reproduce quickly.

Blue Moscow Guppies are prolific livebearers and will usually breed readily in a suitable aquarium. Keep one male with two or three females to reduce persistent courtship, and provide dense plants such as Java moss or floating cover for fry to shelter in. Females give birth to free-swimming young after a gestation of roughly 21–30 days, although timing varies with temperature and conditions. Adults may eat the fry, so a separate breeding tank or heavily planted nursery area improves survival. Feed the fry powdered flakes, infusoria-style foods and newly hatched brine shrimp.

Males are smaller and more vividly coloured, with a modified anal fin called a gonopodium and often a broad, flowing tail. Females are larger and deeper-bodied, usually less intensely coloured, with a rounded abdomen and a visible gravid spot near the rear of the belly when carrying developing young.