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spawn impossible.
The discovery of water chemistry
It can justifiably be assumed that it was the
Harlequin Rasbora, along with the ambition
of aquarists to breed the species, that
eventually led to the discovery of the secrets
of water chemistry that first made possible
the breeding of blackwater fishes. In
Thuringia,where the first successful breeding
tookplace,thewater fromthemains supply is
unusually soft and slightly acid. Gradually
people came to realize that it was these
chemical conditions that were required for
the spawn of so-called problem fishes to
develop.
Numerous local variants - or species?
Because we were reliant for so long on wild-
caught stocks, people quite soon realized
that Harlequin Rasboras fromMalaysia had a
far higher percentage of red than those from
Indonesia, which looked more bluish.
Nowadays we know from DNA study that
they may even be different species.
Wild-caught Harlequins are hardly ever seen
in the trade nowadays. However, the various
breeding strains consist of several
genetically-distinct lineages. Obviously the
crossing of these strains is likely to encourage
the creation of cultivated forms, such as can
be seen among the live-bearing toothcarps,
many cichlids (e.g. discus and angels), and
other ornamental fishes.
Blue and gold
For many years now there have been two
mutant forms of the Harlequin Rasbora in
the trade.The first is a melanic form,in which
the black pigment on the body isn't
restricted to the triangular spot but covers a
large part of the body. This form is
particularly attractive by virtue of there
being a blue sheen all over the fish.
The second mutant is completely the
opposite of the melanic form. It largely lacks
black pigment on the body.Such individuals
are termed leucistic, or - because it sounds a
lot nicer - golden. The golden Harlequin has
been bred and offered for sale by breeders
for several years now.
A ripe female of the new albino cultivated form.These fishes are completely lacking any black pigment,
and hence the eyes are red.
Brand new:the albino
The albino harlequins that have recently
appeared on the market are apparently
totally independent of the blue (melanic) and
golden (leucistic) forms. They are being
offered for sale by the ornamental-fish
wholesaler Höner in Hiddenhausen, Ger-
many, from whom we obtained the
individuals illustrating this article. Thanks
again for that! The albino strain is particularly
beautiful by virtue of the fact that the original
black triangle now appears white.This makes
the fishes look extraordinarily extravagant.
Easy to keep
Breeding them may require a certain
amount of knowledge, but anyone can keep
Harlequins. These fishes are extremely
peaceful, easily fed with dry foods, and
gorgeous to look at. Water chemistry is
unimportant for maintenance. Almost 110
years after the first importation, anyone can
enjoy the satisfaction of keeping Harlequin
Rasboras in the aquarium. Which is a good
thing!
The blue cultivated form of the Harlequin
Rasbora.
Pair of the blue Harlequin Rasbora.
Golden cultivated form, male.
Female of the golden cultivated form.
