his is one of
the few catfishes in the earlier days of the hobby
that was enough to make you into a catfish 'freak'
along with Synodontis angelicus, flavitaeniatus
and decorus of this same family, the Mochokidae.
These days it is the colourful Loricariids such as
the 'Zebra Plec' and the 'Golden Nuggets' that bring
new blood to the catfish fraternity.
Synodontisnigriventris was first described in 1936 and
caused quite a stir when it was first exported in
1950. One of the first articles on 'the curious
fish that swam upside down'was by Fraser-Brunner
in the November 1950 edition of Aquarist &
Pondkeeper and he pointed out that this upside-down
catfish may have been new to the aquarium hobby but
was not new to the ancient Egyptians who frequently
depicted them in their wall-paintings and engravings.
Now the question:
'why do they swim upside down'?. You will notice that
the body colour is reversed with the emphasis on the
belly being darker as with most other fish this area
is lighter so when looking underneath they merge into
the light that comes from above and the back is darker
to presumably give them some protection from predatory
birds. The reverse is somewhat true of Synodontis
nigriventris as they feed on the surface upside
down. I say somewhat true as the back is only a few
shades lighter and sometimes the difference is not
all that apparent.
A scientific study
was carried out in 1976 on this peculiar upside down
scenario, why doesn't this fish get forced back over
to its 'rightful position'? The swim bladder was normal
and there was nothing untoward about the balancing
organ of the ear, as it resembles that of other catfish,
but what they found was that the nervous circuitry
between the brain and the balancing organ of the ear
is rather special, as it can be reset to zero once
the body has tilted more than a certain critical degree
(about 22 degrees).
The image above shows the correct way to house this
catfish in your tanks. They like to have their bellies
pressed up to a surface and bogwood and branches seem
to be their favourite foible. They also prefer to
be kept in a group where they can interact with one
another. A small to medium sized tank with plants
floating and submerged and branched rootwork is the
ideal environment for this peaceful Synodontis.
There is another
variety named S.nigriventris "zebra".
It may be an undescribed species or it may be just
a colour variety of the normal nigriventris,
only time will tell on this issue. The normal nigriventris
comes from all over the Congo drainage and the "zebra"
variety from the region around the town of Kutu, Bandundu
and Lac Leopold 11 in the Dem. Republic of the Congo.
The genus Synodontis
sports three pairs of barbels 1pair: maxillary, 1
pair: outer mandibular and one pair of inner mandibular
barbels that are branched (filaments). There are only
three species that have filaments on their maxillary
barbels as well as the mandibular, and they are, S.
Congo basin. From Kinshasa to Basonga.
Dorsal: 1/7, Anal: 4/4-9 Characteristic
of this species is the smooth anterior face of the
dorsal spine, the narrow separation of the eyes and
the large size of the eyes.
Palegrey to cream-coloured
with dark brown to black blotches which may run together
to form irregular broad transverse bars. Belly uniformly
black (nigriventris). The fins are often darkly
spotted on a colourless ground.
Care and Compatibility
A peaceful occupant of your
community tank. Should not be housed with aggressive
species such as large Cichlids.
It is one of the
few Synodontis to be bred in captivity although
the few successful attempts have been sketchy and
they have been mostly by accident. There have been
reports that they lay their eggs in a depression in
the gravel and also another report when they laid
them in a PVC pipe and also flowerpots. The young
seemingly revert to the upside down pose when about
10 weeks old. A good
regime for a breeding setup would be to provide pipework
and a few clay flowerpots with a gravel substrate
and the usual plants and wood to make them feel comfortable
thus giving them choices for a hopeful spawning. The
females are more noticeably plumper than the males
and a bit more lighter in colour.
In their native habitats they
feed on insect larvae at the water surface and also
scrape algae of the underside of leaves. A good diet
of a good quality flake food, tablet food, frozen
bloodworm and livefood such as daphnia should suffice.
Ancient name for an undetermined fish from the Nile
(Cuvier 1816). nigriventris: Black belly.
Michael Benjamin; Aquarist & Pondkeeper,
Feb.1986. J comp. Physiol;vol 110,
p 323-331 (1976).