(Kner & Steindachner, 1867)
he Ariidae family is wide spread,
ranging throughout the continents of Asia, Africa, Australasia,
South and Central America and there are about 80 species with
the vast amount of them occurring along sea coastlines, estuaries
and coastal lagoons hence one of the common name of this genus,
Sea Catfishes. Until 2007 this species was known as
Arius graeffei but there has been a name change for the
members of the Ariidae family who reside from Southern New Guinea
and Northern Australia, Arius to Neoarius.
The species we are concentrating on this
month is one of only 5 represented in the freshwater rivers of
Australia and Papua New Guinea, the 'Lesser Salmon Catfish', Neoarius
Make sure that you don't let the p.H. drop too low as they like
it more on the alkaline side. They have appeared periodically
in the tanks of retailers and I would be interested if someone
out there is still keeping this species.One cause for concern
is the poisonous spines of the dorsal and pectoral fins as they
will need to be treated with respect as it can take quite a while
for a wound of this nature to heal up if you are unlucky enough
to be punctured.
Colouration is not terrifiic in this species as they have a dark
brown to blue upper body fading to a white/creamy underbelly.
They are also treated as a food fish in its native habitats, they
are renowned for their good taste if prepared properly but some
fisherman treat them as pests as they can get caught in their
nets and can take a considerable amount of time to disentangle
them, and of course as well as avoiding the sharp spines they
can ruin a net for future use.
One very interesting subject that was thrown up by my enquires
was the homeing device or electrical fields
that this species possesses and below I have reproduced a published
paper from the Australian Defence Science site from Alan Theobald
DSTO Defence and Darryl Whitehead of the University of Queensland
Australia called, Using Fish Sense for Mine sensing.
The superior sensory capabilities of fish may one day
replace conventional sonar as a means of detecting marine threats
such as sea mines. New research sponsored by DSTO's Maritime Operations
Division at the University of Queensland's Zoology Department
is exploring the electro-reception used by various fish species
for possible military applications.
For example, catfish (Siluriformes) and sharks and rays (elasmobranches)
can detect electrical fields as weak as 0.07 and 0.001 microvolts
per centimetre, respectively. Researchers at the University of
Queensland have shown that the Australian salmon-tailed catfish
(Neoarius graeffei) has a sensitivity equal
to or better than any other bony fish. In fact many indigenous
animals, such as platypus and echidna, can detect the very low
electric fields from their prey.
The new research program will target species that inhabit estuarine
waters and, indeed, migrate between fresh and salt water which
have vastly different electrical conductivities. It is hoped that
a good understanding of the physical and biological processes
will result from observing differentpopulations
of the same species.
Diagram of electroreception of its prey
by a catfish (Neoarius
The illustration (above), for example,
shows the changes in heart rate (top) and blood pressure (bottom)
when a voltage of 70 nanovolts is introduced along the sides of
This research has a long way to go before military applications
can be realised. However, if it is possible to replicate the type
of natural mechanism plus the signal processing chain, then an
alternative to sonar could be produced. In the first instance,
noting that the ranges at which fish themselves detect electric
fields is of the order of metres, this work is targeted at the
possibility of detecting mines, which might be buried in the sea
bed and therefore difficult to detect using acoustics.
The basic electro-receptive unit in fishes is the ampullary
organ (shown) which is the ampulla enlarged portion of the canal
containing receptor cells and supportive cells. Receptor cells
are electro-receptive sensory cells and the cup-like cells that
encase them are the supportive cells.
length and structure of the ampullary canals varies greatly between
species and habitats. They can be six centimetres long on the
marine catfish (Plotosus anguillaris), whilst on freshwater
catfish they can be just 0.1 to 0.2 millimetres long. The ampullae
themselves may contain hundreds of sensory cells and species may
have thousands of ampullae over the skin.
In nature only the toothed whales,
such as dolphins and porpoises, have been shown to have evolved
active sonar as a detection mechanism in water. Left
: Darryl Whitehead, University of Queensland with Neoarius
graeffei. Many fish species do,
however, detect water-borne acoustic energy up to a few kilohertz
from sources other than themselves.
Typically marine animals have evolved other sensory systems
such as olfactory, magnetic, electric and tactile, as well as
optical. These systems are used for both detection of prey and
navigation. By contrast, human technology has developed sonar
systems, either passive or active, primarily to detect underwater
objects. Since World War Two, vast military funding has been directed
at the development of complex sonar systems. This research represents
one step in the search for complementary approaches to sonar for
Acknowledgments: Darrryl Whitehead of the University
of Queensland for his permission to use his paper, Using Fish
Sense for Mine sensing.
Dorsal 1/7; Anal 15-19; Pectorals; 1/10 to
1/11; gill rakers on first arch 17 to 22; raker like processes on
back of all gill arches, 12 to 20 on first, 15 to 23 on second,
15 to 21 on third; palatel teeth villiform, in transverse series
of 4 oval patches, inner (vomerine) patches smaller than outer (palatine)
patches, patches may fuse in larger specimens to form two patches
or one large patch across palate; maxillary barbels moderately long,
2.5 to 5.8 in SL, extending to edge of opercle, usually to above
pectoral fin base or midway along pectoral fin length or below dorsal
fin spine in juveniles; head ovate, snout rounded or slightly truncate;
head 3.0 to 3.8 in SL; eye oval, 3.7 to 8.4 (mean 6.1) in HL.
Dark brown, dark blue, fawn or ocher above,
sometimes iridescent, fading to yellowish, cream or white ventrally;
some fish from western Northern Territory with black and cream blotches;
fins tan or bluish brown.
Only N. graeffei and Tachysurus
berneyi out of the 5 species are deemed appropriate for housing
in an aquarium as the rest get way too big for captivity. You would
need a good sized tank of course as N. graeffei
can grow to around 18" and if kept with other fish would need
to be housed with larger Cichlids for instance, as they can be carnivorous,
but as far as my enquiry's have thrown up they can be a good addition
to a larger tank.
This fish and some others of its genus have
an unusual breeding pattern for a catfish, it is a mouthbrooder!.
The male incubates the eggs buccally for 2-4 weeks at at a temperature
of 32c. When hatched the young are relatively large and at 2 months
of age they are about 6cm long. The females ventral fins are modified
into claspers to assist in the retaining of the eggs
as they are extruded. The breeding season in the wild is reported
to be the beginning of the wet season ( spring or early summer).
In its native habitat they feed on insect
larvae, aquatic plants, prawns, crayfish, molluscs and small fish.
In the aquarium they will eat anything given such as earthworms,
chopped liver, frozen brine shrimp, prawns, pellets, tablets and
Neo means "new" in latin and Arius is Derived
from the Greek word Apelos (pronounced Araios) which
means "sanctified by the god of war", and refers
to the bony structure extending from the skull covering to
the powerful thorn of the first dorsal fin ray.
Allen, R.Gerald. Freshwater Fishes of Australia.1989.
Burgess, E.Warren Dr. Atlas of Freshwater & Marine
Ferraris, C.J.Jr. 2007 Checklist of catfishes,
recent and fossil (Osteichthyes: Siluriformes), and catalogue of
siluriform primary types.
Middle diagram & Bottom picture: Australian