|
Australia is home to two closely
related arowana or saratoga species. They are both commonly known as
Australian arowanas or Saratogas. The first species is known by the names:
Northern Saratoga, Jardine Saratoga, Gulf Saratoga, Australian Gold or Pearl
Arowana and Jardini Saratoga (Scleropages jardini). The second species
is called: Dawson River Saratoga, Southern Saratoga, Spotted Barramundi,
Australian Spotted Arowana and Leichardti Saratoga (Scleropages leichardti).
Both species were once known (in Australia and still occuring in other parts
of the world) as Barramundi's, though this practice is to be discouraged as
it leads to confusion with the true Barramundi (Lates calcarifer).
These living fossils have been around for some 20 million years. The genus
name Scleropages means hard leaves, which refers to their scales. The species
name jardini was named after the collector and naturalist Mr F. Jardine. The
name leichardti was from the explorer L. Leichhardt.
|
|
|
The Saratogas are a striking,
rather prehistoric-looking member of the small, ancient and widespread family
of fish, the Osteoglossidae. The body is very laterally compressed, with a
large upturned mouth, big scales and barbels on the lower lip. To differentiate
between the third species of the genus the Asian Arowana (S. formosus),
the number of scales in the lateral line is 32-35 in S. leichardti and
S. jardini while S. formosus has only 21-25. The saratogas are
greenish-grey to brown on the back and coppery-gold (S. jardini) or
silvery-green (S. leichardti) on the flanks. One to three red-orange
spots can be found on each scale of S. leichardti, while S. jardini appears
to have minimal body spots, the majority of these scale spots appear to
have fused creating line markings instead. The fin colours are similar to, or
darker than its body colour. Both species have spots present on their fins
and tail, with S. leichardti having numerous small spots-in-lines and S.
jardini having less but larger spots. The spots may be yellow to orange
to red for S. jardini, with spots usually red-orange for S.
leichardti. The more northern species (S. jardini) commonly shows
a pattern of squiggly lines and or dots on and bordering its gill plate, this
is not present (to my knowledge) in the southern species (S. leichardti).
Another characteristic of S. jardini is its head which slopes downward
from it's back often making it's head look smaller in comparison to it's
body. On the other hand S. leichardti shows no sloping head and is
generally more level with it's back.
|
|
|
Wild saratoga generally weigh from
0.5 to 3kg with specimens recorded exceeding 10kg. The northern species is
generally considered to grow larger than its southern cousin. Spawning of the
northern species commences at the start of the 'Wet' season, which is around October.
The southern species starts breeding around August/September, and the young
are available to the aquarist around November. The Australian Arowana like
other arowanas, is a buccal incubator, in that it carries its eggs (about 50
to 100) in its mouth. When the young hatch they stick with the female (about
5 weeks) and in times of danger she will open her mouth allowing the young to
seek shelter.
Pictures were taken from: Australian Native Fishes for
Aquariums by Leggart and Merrick
|
