|
RNDr. Roman Slaboch
Translate: Eli Slabochova
Knife
livebearer (Alfaro
cultratus /Regan, 1908/) comes from
Central America (from
the south of Nicaragua to the north of Panama).
It is attractively shaped fish with a couple of
unpleasant features. One of them is the
indisposition to take the feed from the bottom. It
is not so big problem; keep them with another
species that cleans the bottom, and the problem is
managed. It can be even any peaceful species of
livebearers, because scharp-belly livebearer
interbreeds only inside of its species. The reason
is quite complicated precopulation observance of the
male, which swims just above the female’s head and
touches her crown with gonopodium. In the next
stadium, male beats with quick motions of gonopodium
on her head. If female doesn’t want to escape, he
goes down, floats beside her, and tries to
inseminate her. It is obvious, that this behavior
formula can’t any other species comply.
Other
inconveniences of the breed are their jumping
performances. Above all, maturing males (4-5 months)
jump often in chases. The biggest losses are
consequently from this period, and it is the case of
the majority of females in aquarium breeds.
Last
but not least, they have unpleasantly high reception
of increased quantity of nitrogen fusions in the
water. Concentration, which other species’ behavior
doesn’t indicate, results in the preterm litters of
the immature young. The breeder recognizes it after
as much as the female doesn’t bear. Generally, after
this time the concentration more increases, fish
have enlarged orbs, stop to take the feed and die.
Periodic exchange of water is consequently vital
condition.
Many a
literature features the taste for running water. But
in my breeds fish avoid the outlet of the filter.
Also the observations from the nature don’t support
this statement directly. But it’s true, that adult
big ones stay in the middle of the strain (if there
is any) and it is good chance to fish them, because
it’s simple to take them with fyke. Literature and
observation in the natural habitats and in the
breeds come to a verdict that A. cultratus
needs bushy planted tank. In the nature it’s made
up with the thicket of roots and fallen branches for
the most part, but the effect of perfect refuge
is the same. Hiding places need first the freshly
born young (8 mm), which tempt the attention
of adults with their jerking motions, and great deal
of the young enrich their feed. In the nature I saw
the smallest young almost entirely in the shallow
places with 0,5-1 cm of water. In 24°C,
the gravidity lasts approximately 24 days and it’s
lowly perceptible.
They
mature after 6 months. Females grow up to even 8 cm,
males maximum 6 cm. On the basic ochre color is
beautiful metallic blue glaze, which excels only at
the exposure of sunshine. Czech specific epithet
scharp-belly was assigned because of keel ordering
of the scales on belly.
The fish also “enjoyed” scientific descriptions:
-
Alfaro
cultratus
Regan, 1908;
-
Petalosoma cultratus
Regan, 1908;
-
Petalurichthys cultratus
Regan, 1912;
-
Alfaro
acutiventralis Meek,
1912;
-
Petalosoma amazonum
Regan, 1911;
-
Petalurichthys amazonum
Regan, 1912;
-
Alfaro
amazonum
Regan, 1913;
Mr.
Regan was evidently at loose ends.
Due to
unusual character of the shape, Alfaro cultratus
is one of the few wild livebearers, which are
available in akvashops.
Resources:
Wischnath, L.,(1993): Atlas of Livebearers of
The World, T.F.H. Publications, Inc.; USA, 336 ss.
|
