NEWS 115
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The Harlequin Rasbora is one of the most important ornamental fishes on
Earth. It was first discovered in 1904 by the German researcher Georg Duncker
of the Zoological Museum in Hamburg during an expedition to Malaysia, and
scientifically described as
Rasbora heteromorpha
.
A new cultivated form of
the Harlequin Rasbora
by Roman Neunkirchen
Cultivated forms
the specialist magazines of those days,where
it is still available to read today. It was
suggested, for example, that the females
looked totally different to the males and the
A male of the new albino cultivated form of the Harlequin Rasbora. All photos: Frank Schäfer
he name
heteromorpha
means ”having
a different form”. D
UNCKER
used it to
express the fact that the new discovery was
appreciably higher-backed than all the other
Rasbora
species known at that time. For this
reason the Harlequin Rasbora, along with a
number of subsequently-discovered, related
species,is placed in the genus
Trigonostigma
,
whichmeans "triangle spot”.
Impossible to breed?!
The first importation for the aquariumhobby
took place shortly after the discovery of the
species. In 1906 Julius R
EICHELT
of Berlin
managed tobringa fewspecimens toEurope
under arduous conditions.But despite all the
experience of breeding aquarium fishes
already available at that time, this gorgeous
little fish couldn't be bred!
T
Wild-caught male Harlequin Rasbora.
Evil rumors
Anyone who thinks that disputes and back-
biting are an invention of the Internet era is
going to be severely disappointed to learn
that even in the early 20th century aquarists
were past masters of this art! The difference is
that people didn't defame their fellow
humans on Internet forums back then, but in
wicked Chinese in Singapore were sending
only males, in order to maintain their
monopoly on the Harlequin Rasbora.It wasn't
until 1920 that the plot unraveled, when a
Herr Gundelach in Thuringia became the first
person to breed the species successfully in
small numbers.
Breeding secrets
Two factors are particularly important for the
breeding of the Harlequin Rasbora: the water
chemistry and the spawning plants.The latter
is almost more important. Until that time
people hadbeen accustomed to all barbs and
rasboras scattering their eggs among fine-
leaved aquatic plants. And so they put what
they thought were a pair in a breeding
aquarium with a clump of plants of this kind.
They would have had to wait for a very long
time for anything to happen! Unlike (almost)
all other barbs and rasboras, the triangle-spot
rasboras spawn on the undersides of the
leaves of broad-leaved plants. After initial
driving by the male(s) the female takes the
initiative, swimming beneath a leaf and
turning onto her back.The female remains in
this position for some time. If a male follows
then spawning takes place, with the female
being held in a U-shaped embrace by the
male. Triangle-spot rasboras exhibit this
behavior even in water whose chemical
composition makes development of the
