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his member of the Mochokidae family has been quite a popular if not too attractive addition to the catfish fraternity since 1973 when it had then been made the emblem of the now deceased Catfish Association of Great Britain.

Synodontis batensoda

The original description was Synodontis batensoda, named by the German Ichthyologist W.P.E.S Rüppell in 1832 in his paper "Continuation of the description and figure of several new fish, in the Nile. p1-14 ." It was known as this name until Bleeker in 1862 erected a new genus, Brachysynodontis for it. This was because of the differences between the numbers of gill rakers and the absence of a gap between the dorsal and adipose fin. This is still an ongoing debate after it was moved back into the Synodontis genera again.

Synodontis batensoda

As its colour pattern suggests, it spends most of its time in an inverted position. In the wild they congregate in large shoals, feeding on phytoplankton, zooplankton and detritus. It is speculated that one of the reasons for the inverted swimming position is that when caught in dry season pools it gives this species the opportunity to exploit the low oxygen content to the full. They are found in some of the largest rivers in Africa, but migrate to areas where the pools and marshes occur. I can only surmise that this is a pre-empt to spawning for Synodontis batensoda.

The common name of "Upsidedown catfish" may confuse readers as the other Syno also with this name is the smaller Synodontis nigriventris which unlike S. batensoda spends most of its time inverted under branches or logs whereas the latter when dormant sits on the bottom of the aquarium.

The genus Synodontis sports three pairs of barbels 1 pair: 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. clarias, S. decorus and S. flavitaeniatiatus.

This is an other 'Synodontis' which has appeared as hieroglyphics on the walls of ancient Egyptian tombs along with S. schall, S. membranaceus, S. serratus, S. frontosus and S. sorex.

Giant upside-down catfish

Synodontis membranaceus, Synodontis melanogaster, Hemisynodontis membranaceus, Brachysynodontis batensoda

Mochocinae

Africa: Nile, Chad, Niger (including the Bénoué), Senegal and Gambia basins.

17.5cm. (7ins)

23-27°C (73-81°F)

6.0-7.2.

Dorsal:1/7, Anal:5/7-9. Maxillary barbels with a broad posterior membrane throughout their length; mandibular barbels without membrane and possessing slender ramifications. Shoulder-process rectangular. Adipose fin very large. Dorsal fin spine smooth anteriorly, occasionally with 3-4 serration's at the tip, feebly serrated posteriorly ending in a filament. Pectoral fin spine feebly serrated on outer border strongly serrated on inner border. Caudal fin forked, each lobe ending in a point. Head shield pitted and granulated.

Adults are silver-green to blue-grey, occasionally delicate redish-brown. Underside blackish. Fins grey, partly with dark spots. Barbels black.The young have large dark blotches on the flanks, separated by an intervening pale network.

Keeping S. batensoda in the aquarium poses no problem as they are in my experience an easy going Synodontis and can be quite entertaining in their forages around the tank swimming upside-down along the top of the tank and then reverting to their bottom posture as they glide along the bottom. I have found that they sometimes can get bullied by the more aggressive members of this family so as with all Syno's you will have to experiment to find the best solution for its tankmates.

Not recorded.

Omnivore, in its natural habitat it feeds on plankton, algae and detritus. May also feed on surface insects, chironomid larvae, benthic crustaceans and mollusks. In the aquarium they will take a wide range of foods. They will feed during the day and accept live food, frozen food (bloodworm) tablet and pellet foods and a good quality flake. I have also witnessed my specimen gnawing away at a piece of courgette (zucchini) which was left out for my Ancistrus, so a little bit of greenery now and again would also supplement their diet.

Synodontis: Ancient name for an undetermined fish from the Nile (Cuvier 1816).

Catfish Association of Great Britain Volume 1 1983.
Froese, R. and D. Pauly. Editors. 2002. FishBase. World Wide Web electronic publication. www.fishbase.org, 19 August 2002.
Gosse, J.-P., 1986. Mochokidae.. p. 105-152. In J. Daget, J.-P. Gosse and D.F.E. Thys van den Audenaerde (eds.) Check-list of the freshwater fishes of Africa (CLOFFA). ISNB, Brussels, MRAC, Tervuren; and ORSTOM, Paris. Vol. 2.
Rüppell W.P.E.S., Continuation of the description and figure of several new fish, in the Nile p1-14, 1832.
Sterba, Günther. Sterba's Freshwater fishes of the World no1.

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