Bleher’s Rainbowfish - Chilatherina bleheri

Bleher’s Rainbowfish (Chilatherina bleheri)

Bleher’s Rainbowfish, Chilatherina bleheri, is a striking freshwater rainbowfish from Indonesian New Guinea recognised by its elongated body, shimmering silver to blue-green front half and warm orange to red colouration developing towards the rear of mature males. Adult males display the strongest colours, particularly when competing or courting, while females and juveniles are generally more subdued. This active schooling species naturally inhabits Lake Holmes within the lower Mamberamo River system and thrives in spacious aquariums with clean, well-oxygenated water, open swimming space and a planted perimeter.

Common Name:
Bleher’s Rainbowfish, Bleher’s Rainbow, Bleheri Rainbowfish.

Scientific Name (Latin):
Chilatherina bleheri

Maximum Size:
Approximately 12 cm standard length when fully grown.

Water Type:
Freshwater

Origin / Natural Habitat:
Endemic to Indonesian New Guinea, where Chilatherina bleheri is known from Lake Holmes, also called Danau Bira, within the lower Mamberamo River system.

This highly restricted natural distribution makes the species of particular conservation interest. It inhabits tropical freshwater environments where groups swim through open water while remaining close to vegetation and other forms of shelter.

Water Parameters:
Temperature: 23–27°C
pH Range: Approximately 7.0–8.0
Hardness or Salinity: Approximately 8–15°dGH; moderately hard, mineral-rich freshwater is preferred.

Temperament:
Peaceful, active and social. Bleher’s Rainbowfish are best maintained in groups and generally coexist well with similarly sized peaceful community fish. Males may display energetically towards one another, particularly when competing for females, but serious aggression is uncommon when sufficient swimming room and group size are provided. Avoid keeping this active species with very timid or extremely slow-moving fish that may be intimidated during feeding.

Diet:
Omnivorous. Rainbowfish naturally consume small aquatic invertebrates, insects, zooplankton, algae and other fine organic material. In the aquarium, offer high-quality tropical flakes, granules or small pellets as the staple diet. Supplement with frozen or live Artemia, daphnia, Cyclops, mosquito larvae, bloodworms and mysis shrimp. Include spirulina and other vegetable-rich foods to provide dietary variety.

Feed small varied portions once or twice daily.

Minimum Tank Size:
A minimum aquarium volume of approximately 250 litres is recommended for a group, with a long footprint and generous open swimming space. A group of at least six individuals is strongly recommended, with larger groups providing more natural schooling and display behaviour.

Behaviour & Activity:
An energetic mid- to upper-water schooling fish that spends much of the day swimming through open areas of the aquarium. Mature males develop substantially stronger colouration than females, with the rear half of the body becoming orange, red or bronze while the front may show blue-green, silver or iridescent tones. Male colour intensity may increase dramatically during courtship and social displays. Dominant males frequently extend their fins and swim alongside rivals or females to advertise their condition. Females tend to remain more silver or olive overall and usually have less intense orange-red colouration.

Bleher’s Rainbowfish are egg scatterers. Spawning typically occurs among fine-leaved plants, mosses or spawning mops, where small adhesive eggs are deposited over a period of several days.

Aquarium Category:
Community Fish

Bleher’s Rainbowfish are excellent inhabitants for spacious freshwater community aquariums containing other peaceful, active species with similar water requirements. Suitable companions include other Rainbowfish, larger peaceful Tetras, Danios, Barbs, Corydoras, peaceful Loaches and appropriately sized community catfish. Avoid very small, timid fish and species requiring strongly acidic or exceptionally soft water.

Special Requirements or Care Notes:
Maintain Bleher’s Rainbowfish in a group of at least six individuals. Larger groups of eight or more generally produce more natural behaviour and stronger male displays. Where possible, maintain a balanced sex ratio or slightly more females than males. This helps distribute courtship attention and allows several males to display without continually targeting one female. Provide a long aquarium with substantial open swimming space. Dense planting can be concentrated along the sides and rear while leaving the centre open. Use floating vegetation or tall plants around the aquarium perimeter to create security without restricting swimming space.

Maintain clean, well-oxygenated water with efficient biological filtration and regular partial water changes. Rainbowfish are active swimmers and perform best in aquariums with excellent water quality. Moderate water movement is beneficial, but ensure calmer areas remain available around planted sections. A varied diet rich in small crustaceans and high-quality prepared foods helps mature males develop their strongest natural colouration. If breeding is desired, provide fine-leaved plants, Java moss or spawning mops. Adults may consume eggs and newly hatched fry, so eggs can be transferred to a separate rearing aquarium. Feed newly hatched fry microscopic foods initially, progressing to newly hatched Artemia and finely powdered foods as they grow. A secure aquarium cover is essential because Rainbowfish are strong jumpers and may leave the aquarium when startled or during energetic chasing. Because Chilatherina bleheri has an extremely restricted natural range and is considered threatened in the wild, responsibly sourced captive-bred specimens should be preferred wherever available.

Suitable for:
Intermediate freshwater fishkeepers

Availability:
Rare or occasional in trade

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.