Japanese Blue Endler Care Guide - Aquarium Tips, Diet & Breeding

The Japanese Blue Endler is a selectively bred colour form of Endler’s livebearer, prized for the intense blue markings that cover much of the male’s body. Depending on the line, males may show metallic blue across the flanks with darker accents and subtle secondary colours in the tail and dorsal fin. Their compact size and bright patterning make them especially eye-catching in planted aquariums.

Males are active, alert and constantly on the move, displaying to females with quick, energetic movements. They are generally peaceful, although males may pursue females frequently, particularly when too few females are present. Females are less vividly marked and have the rounded, practical shape typical of livebearing poeciliids.

In the wild, Endlers inhabit warm, shallow waters including lagoons, ponds, slow-moving streams and drainage channels. These environments often contain aquatic vegetation, algae and leaf litter, giving the fish plenty of cover while providing rich feeding grounds for small invertebrates and microorganisms.

Japanese Blue Endlers are among the hardiest small livebearers available, but their selective-bred colouration is maintained through careful line breeding. They can hybridise readily with common guppies, so aquarists who wish to preserve the strain should keep them separate from Poecilia reticulata and other Endler varieties.

Poecilia wingei is native to northeastern Venezuela, particularly the Laguna de Patos area near Cumaná and connected coastal drainage habitats. The Japanese Blue Endler is a selectively bred aquarium strain rather than a distinct wild population, developed for its vivid blue coloration.

A minimum aquarium of 40 litres is suitable for a small group, with a footprint of approximately 60 × 30 cm giving them useful swimming length. Use a secure lid because Endlers can jump, and provide gentle to moderate filtration with good oxygenation. A fine gravel or sand substrate works well, accompanied by hardy plants, floating cover, driftwood and other refuges for females and fry. Leave open areas for active swimming while keeping the aquarium mature and stable.

Males reach about 2.5 cm (1 inch), while females can grow to approximately 4 cm (1.6 inches).

Offer a varied diet of quality crushed flakes, small granules and appropriately sized live or frozen foods such as baby brine shrimp, daphnia and cyclops. They also graze on soft algae and aufwuchs, so a small vegetable component or spirulina-based food is useful. Feed small portions once or twice daily, with enough variety to support colour, growth and breeding without leaving excess food in the aquarium.

Japanese Blue Endlers suit peaceful community aquariums containing similarly small, non-aggressive fish. Suitable companions include pygmy corydoras, small rasboras, ember tetras, peaceful small danios, otocinclus and other calm livebearers. Avoid large or predatory fish, fin-nipping species and boisterous tankmates that may eat the fry or outcompete these small fish. Do not house them with common guppies or other Endler strains if maintaining a pure Japanese Blue line is important, as they will hybridise.

Japanese Blue Endlers breed readily in a mature aquarium. Keep one male with two or three females to reduce persistent attention, and provide dense floating plants or fine-leaved cover for fry. Females usually release between 10 and 40 free-swimming young after a gestation of around four weeks. Adults may eat the fry, so separate them or provide plenty of hiding places; feed the young powdered flakes, baby brine shrimp or other suitably tiny foods.

Males are much smaller and more colourful, with elongated bodies, vivid blue patterning and a gonopodium. Females are larger, plainer silver or grey, and have a rounded abdomen; mature females may also show a dark gravid spot near the rear of the body.