Harlequin Rasbora - Aquarium Maintenance

Aquarium Maintenance

Despite the relatively uniform water chemistry of its various habitats, the Harlequin Rasbora is an adaptable fish in the aquarium, provided that migration of the fishes to waters of differing chemical parameters is conducted with due care. The fish will live in an aquarium in waters ranging from a pH of 6.0 to 7.8, and hardness ranges from zero to 15°dH. However, whilst for maintenance purposes water chemistry is not critical provided that cleanliness of the aquarium is maintained, for breeding purposes the water chemistry becomes considerably more so (see below). The temperature range of the Harlequin Rasbora is usually cited as 22°C to 27°C (72°F to 81°F) (for example, Walker, 1971, p.101) but the fish is capable of living in temperatures from 21°C to 28°C, and indeed usually breeds at around 28°C (82.4°F).

The Harlequin Rasbora is a shoaling fish, and should be kept in a group comprising a minimum of six individuals, though shoals of larger numbers are preferable not only from the standpoint of the well-being of the fish, but from an aesthetic standpoint - a large shoal of Harlequin Rasboras presents a striking vista even to non-fishkeepers, and their active disposition in the water adds to the spectacle. Being a peaceful species, the Harlequin Rasbora may be maintained in a community aquarium setup with other similarly sized and peaceful aquarium fishes, including many of the small Characins from South America (the similarity in water chemistry of the two habitats for these different fishes has already been covered), assorted small Barbs, Danios, other small Rasboras, Corydoras catfishes, Otocinclus catfishes and others.

An aquarium intended to house Harlequin Rasboras should be planted with live plants, with some open areas for swimming provided between stands of plants such as Cryptocoryne species, these being among the plants that inhabit the Harlequin Rasbora's native waters. Likewise, some Asiatic species of Aponogeton may be utilised. Bushy plants such as Cabomba may also be used in the aquarium, but this genus of plants requires intense lighting, while the Cryptocoryne and Aponogeton species prefer more subdued lighting, as does the Harlequin Rasbora, so if the aquarist wishes to have a variety of plants in the aquarium, other species that prefer subdued lighting are better choices. Filtration should provide modest currents (most of the home watercourses inhabited by the fish are relatively slow moving) but still provide sufficient filtration turnover to maintain aquarium cleanliness.

Feeding the Harlequin Rasbora presents no problems to the aquarist, as the fish enthusiastically accepts prepared foods, though for best health, a variety of these should be given, preferably interspersed with feedings of live foods such as Daphnia. For breeding purposes, conditioning with live foods is likely to boost success by a considerable margin, though even heavy live feeding will not induce spawning if the water chemistry is incorrect (see below). If available, mosquito larvae make an excellent conditioning food for this species.

The lifespan of the Harlequin Rasbora has not been systematically determined, but individuals in the aquarium can be expected, with good care, to live for 5 to 6 years.