Harlequin Rasbora (Trigonostigma heteromorpha)

Harlequin Rasbora Trigonostigma heteromorpha
Name	Harlequin Rasbora
Name Lat.	Trigonostigma heteromorpha
Synonym	Rasbora heteromorpha
Family	Danios
Family lat.	Danionidae
Order	Carps
Order lat.	Cypriniformes
Origin	Southeast Asia
Habitat	Forest streams, ponds
Diet	Carnivore
pH	5.0-7.5
Behavior	Peaceful
Keeping	Group
Care Level	Moderate
Reproduction	Substrate spawner
Breeding	Difficult
Life Span	4-6 years
Protection	No
Metric Units
Size	4-5 cm
Temperature	21-28 °C
Hardness	< 12 °dH
Aquarium	~ 60 l
US Units
Size	1.6"-2"
Temperature	70-82 °F
Hardness	< 214 ppm
Aquarium	~ 15 gal

Distribution and habitat

The wedge spotted danios are widespread in the south of Thailand, the Malay Peninsula as well as on Sumatra and Borneo. They live in weedy pools and in slow-flowing, shady forest streams with dense underwater vegetation and clear, slightly acidic water.

Maintenance

The aquarium should have a varied planting (mainly Cryptocorynen), which offers both shelters, as well as swimming space and roots, which serve as a retreat. With shaded light (floating plants) and a dark substrate covered with some foliage (sea almond leaves) they show the most beautiful coloration.

No ammonia, ammonium and nitrite should be detectable, the nitrate value should not exceed 100 mg/l. To ensure the water quality and oxygen content, a filter and heater adapted to the aquarium size is required, as well as lighting for the species-appropriate day-night rhythm of the animals.

Diet

In nature they feed on insects, insect larvae and plankton. The food supply consists of live, frozen and dry food. For a balanced diet, feed once a day with a high-quality, protein-rich dry food (flakes, granules, pellets) as well as cyclops, moina, daphnia, artemia, etc. (live or frozen)

It is recommended to feed small portions several times a day. Only feed as much as will be eaten within a few minutes. A regular and varied diet promotes health and increases resistance.

Behaviour and compatibility

They are lively and very peaceful schooling fish that can be socialized well with other small, peaceful fish. At least 5, but preferably much more Keilfleckbärblinge should be kept together.

Basically, only compatible fish species with similar requirements for water conditions and water temperature should be socialized.

Sex dimorphism

The wedge spot tends to run straight out in the male, while it is curved in the female.

Reproduction and breeding

The male usually swims around (drifts) the female in the early morning, which spawns on the underside of aquatic plant leaves, preferably Cryptocorynes. The parents do not engage in brood care and should be separated from the fry after spawning, as they are spawn predators. The larvae hatch after about 24 hours and swim freely after one week

Fry must be fed several times a day with special rearing food (Artemia nauplii, dust food). In a community tank breeding is hardly possible, because the spawn is easy prey.

Important

Wedge spot danios are bred in several color variations.

The foliage (sea almond tree, oak, etc.) enriches the water with humic substances, naturally lowers the PH value and is a valuable secondary food source.

The well-being of the fish should be checked regularly. Temperature should be checked daily, pH, hardness and nitrate levels should be checked at least every 14 days. Regular partial water changes are recommended, even when contaminant levels have not yet reached the upper limit. Sudden changes in water quality should be avoided. Newly introduced fish must be accustomed slowly to the water in the aquarium.

Further literature can be found in your pet store.

References

Text: Werner Winter; Image: petdata

Source: BMEL (1998): Tierschutzgutachten - Haltung von Zierfischen (Süßwasser); RIEHL & BAENSCH (2006): Aquarien Atlas Bd. 1, Mergus Verlag; ENGELMANN (2005): Zootierhaltung - Tiere in menschlicher Obhut: Fische, Verlag Harri Deutsch

• Gemäß § 21 Abs. 5 Tierschutzgesetz idgF