Excerpted From:
So
you think livebearers are boring? There's more to livebearers than guppies. Neale Monks
looks at some of the interesting and unusual livebearers
available to aquarists by Neale
Monks
The Hemirhamphridae
While at least half a dozen species of
halfbeak are commonly traded, retailers simply divide them up
into Celebes halfbeaks for the various species of
Nomorhamphus, and silver (or wrestling) halfbeaks, which
cover species of Dermogenys. Celebes halfbeaks are larger
and more colourful, but they have a reputation for being rather
delicate and short-lived fish. This is almost certainly because
retailers do not correctly identify the different species sold,
and not all species have the same water chemistry requirements.
The most commonly traded species is Nomorhamphus liemi,
the true Celebes halfbeak, which needs slightly soft and acid
water to do well. By contrast, the red-fin halfbeak,
Nomorhamphus ebrardtii, the next most commonly sold
species, must have hard and alkaline water to do well.
Distinguishing these two species is fairly easy: Nomorhamphus
ebrardtii have straight beaks and red or orange fins, whereas
Nomorhamphus liemi have curly beaks and red, black, and
blue fins. A few other species are sometimes sold as Celebes
halfbeaks, and generally these resemble Nomorhamphus liemi
in terms of water chemistry requirements.
Silver halfbeaks, on the other hand, are
very hardy, and though they lack the bright colours of the
Celebes halfbeaks, they have more 'halfbeaky' shape, with
a nice long snout and a very streamlined shape. There are
probably three different species of Dermogenys sold under
the silver halfbeak name, and all will tolerate a broad range of
water chemistry values. They will even do well in slightly
brackish water.
In terms of care, these are fairly
straightforward fish. Flake foods are readily taken, though for
breeding purposes, conditioning the fish with frozen or live
foods is essential. Bloodworms, daphnia, fruit flies, and other
small invertebrates are particularly favoured. Silver halfbeaks
feed almost exclusively from the surface, while Celebes halfbeaks
are much more midwater fish, and will even take food from the
substrate. All halfbeaks are jumpy, easily startled fish, and
ensuring the tank is covered at all times is essential. Floating
plants will help to settle these fish into the aquarium, as well
as providing the fry with somewhere to hide. One peculiar
characteristic of the halfbeaks generally is the high level of
aggression they display to one another. Females are only
marginally less aggressive than males, and both sexes will engage
in short chases and fights. Although males do not fight to the
death, the cumulative stress of being bullied by a dominant male
can lead to the premature death of other males in the tank. For
this reason, halfbeaks should be kept in either a big group (over
a dozen) or in a smaller group with only a single male.
Halfbeaks are fairly easy to breed;
about the only problem is keeping the mother happy and healthy
through the gestation period. Unlike most other livebearers,
miscarriages are common with halfbeaks, perhaps due to their
nervous temperament. Once born though, the baby halfbeaks are
tough and easy to raise, and will immediately accept newly
hatched brine shrimps, small daphnia, frozen lobster eggs, and
finely ground flake food.
|