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Synodontis schall  (Bloch & Schneider, 1801)


ack in September 2002 we highlighted the aggressiveness of Synodontis acanthomias and then went on to mention its partner in crime, Synodontis schall, and 6 years to the day (Sept. 2008) the spotlight now falls on this species from the Mochokidae family.

 

Synodontis schall


The original description of S. schall is somewhat patchy as the type speciman, which was lodged in the ZMB (Poll 1971; Paepke 1999; Ferraris 2007), was lost. It was originally described from the Nile basin.

 

A recent paper by Tobias Musschoot and Philippe Laleye (May 2008) stated that they carried out a morphometric study of 105 specimens of Synodontis schall, including most type specimens of all nominal species considered junior synonyms of S. schall. Two new species S. ouemeensis and S. kogonensis are described from the Ogun (Nigeria), Oueme (Benin) and Mono (Togo) basins, and the Kogon and Fatala (Guinea) basins, respectively. A neotype is designated for S. schall. The two new species differ from S. schall mainly by the width of the premaxillary toothplate (12.9–24.3% HL for S. schall vs. 21.6–32.7% HL), and can be distinguished one from the other by differences in orbit diameter (20.5–26.8% HL for S. ouemeensis vs. 19.4–21.0% HL for S. kogonensis) and prepectoral length (23.4–28.2% SL for S. ouemeensis vs. 21.6–23.3% SL for S. kogonensis).

 

It is also thought that Synodontis robbianus is a synonym of S. schall (Willoughby, N.G., 1994) but more work has to be carried out in Lake Lake Kainji on more specimens. My own thoughts are maybe not, as I have kept S.robbiana and I did not note any aggression what so ever with this species, but we will find out in due course.

 

Synodontis schall

 

There are quite a few colour varients to this species (see colour section below) and it depends on where a certain speciman originates from as S.schall is one of the few Synodontis species with a very large geographical distribution. It is known from practically all West African basins, except for the coastal basins of Sierra Leone and Liberia (Paugy and Roberts 1992; Paugy et al. 1994). The species is also known from the Nile basin, Uebi Giuba (=Uebi Shebeli), and Lakes Abaia, Stephanie, Turkana (=Rudolf) and Tchad (Poll 1971; Paugy et al. 1994).

 

Acknowledgements: Tobias Musschoot for his permission to use extracts from his paper on Synodontis schall.

 


Characteristics
Predorsal profile more or less straight; head subconical when viewed dorsally; snout rounded, sometimes slightly pointed when viewed dorsally; maxillary barbels without membrane, or with a hardly visible membrane; gill opening from level of eye (variably between upper and lower margin), down to level of pectoral spine base; occipito-nuchal shield terminating posteriorly with two usually rounded, rarely more pointed, processes on each side of the dorsal fin; maxillary barbels almost reaching posterior tip of humeral process, rarely beyond, unbranched; external mandibular barbels with filaments, reaching base of pectoral fin; internal mandibular barbels with short filaments, reaching a vertical from anterior, sometimes posterior, margin of eye; anterior nostrils tubular with small lateral flap, posterior nostrils with flap along anterior margin; eye superolateral; orbit with free margin; mouth inferior; teeth unicuspid; 18–32 mandibular teeth; humeral process usually without ridge along the ventral margin, upper margin straight or a little concave, lower margin straight or a little convex; proximal part of lateral line positioned above mid-lateral line; anterior side of dorsal spine smooth or with some very fine serrations proximally and with some larger serrations distally, posterior side clearly serrated, mainly distally; dorsal fin spine slightly curved backwards; adipose fin height very variable; adipose fin well developed with a convex, sometimes rather straight, margin with a variable slope; caudal fin deeply forked, upper lobe a little longer than lower; anterior side of pectoral spine with fine serrations proximally, becoming a little larger distally, but often none at the tip, directed outwards, posterior side with less but marked serrations along its entire side, which are directed towards the body; pelvic fins inserted at the level of the adipose fin origin or a little before, posterior margin usually straight, not or barely reaching anal fin base; anal fin reaching beyond a vertical through the posterior margin of adipose fin; urogenital pore and vent positioned at the level of the adipose fin origin or a little beyond.

Colour
Variable; generally body brown or grey dorsally, becoming lighter on the flanks, belly light brown or grey or whitish (specimens from Agneby River dark grey, those from Benue River dark brown, with lighter belly); humeral spot present; barbels either whitish or brown, including filaments; adipose, dorsal and caudal fin more or less the same colour as dorsal body surface; pectoral, pelvic and anal fins whitish or grey or brown, usually depending on body color, sometimes relatively dark (specimens from Agneby River). Smallest specimens (around 50mm SL): small dark spots (,1 mm) all over body, except ventrally but including all fins (except sometimes the pelvic fins); sometimes marbly or mottled on body or with some larger irregular pale spots; sometimes with larger dark spots (.1 mm) on adipose, dorsal and caudal fins. Larger specimens (below about 100mm SL): variably with or without small dark spots (,1 mm), mainly on dorsal body surface and flanks above lateral line, including the adipose fin; usually disappear in specimens larger than about 100mm SL, but still present on some specimens from Senegal (Rivers Gorom and Lampsar), Uganda (Lake Albert) and Black Volta (in the latter they also occur below the lateral line).

Compatibility

A very robust fish and would need to be housed with large companions who will be able to look after themselves. Even large Pleco's will suffer by this species (editors own observation)

Breeding

Unreported.

Sexual differences
The males will be slimmer than the females.

Feeding
Anything and everything!. Meaty foods are relished. Will also eat any foods given to your other tank inhabitants and will also take flakefood that floats to the botom. Feed also tablet foods and frozen bloodworm which they find a favourite.

Glossary of Terms

Type specimen: The species of a genus with which the generic name is permanently associated; the description of a genus is based primarily on its type species, being modified and expanded by the features of other included species.

Neotype : Specimen which replaces Holotype when lost.
Synonym: Different name for the same fish.
Premaxillary: In relation to the premaxilla (an upper jaw bone) e.g. premaxillary tooth band.
Maxillary barbels: Pertaining to the upper jaw. (maxillary barbels)
Occipito-nuchal shield: A median bone on the upper surface of the back of the head; pertaining to the occiput.

Humeral process: Bony extension of the pectoral girdle.

Fontanel: The space(s) between the bones on top of the skull covered by skin..
Anal Fin: The fin forward from the anal cavity.

Dorsal fin is defined as the medial fin on top of back.
Caudal fin is defined as the tail fin.
Pectoral fins are defined as paired lateral fins.
Pelvic fins are defined as paired ventral fins between the pectoral and anal fins.


Etymology

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

schall: Derived from the northern Egyptian arabic dialect name of this fish, shâl, written with "sch" because Bloch & Schneider were German speaking biologists.

References

Musschoot, T. and P. Lalèyè, 2008 Designation of a neotype for Synodontis schall (Bloch and Schneider, 1801) and description of two new species of Synodontis (Siluriformes: Mochokidae). Journal of Natural History 42(17-18):1303 1331).

Willoughby, N.G., 1994. The taxonomy of the genus Synodontis (Pisces: Siluroidea) in Lake Kainji, Nigeria. African Journal of Tropical Hydrobiology and Fisheries, 5(25):25-30

 

Photo Credits

 ©  Hippocampus Bildarchiv


Factsheet 147

Synonyms:
Silurus schall, Hemisynodontis schall, Leiosynodontis maculosus, Pimelodus schall, Synodontis clarias, S.arabi,  S.maculosus,  S. smithii
Common Name:
Schall's Synodontis
Family:
Mochokidae  
Subfamily:

 

Distribution:
Africa: Nile basin, Abaia, Stephanie, Rudolf Lake, Tana?, Uebi Guiba (Uebi Shebeli), Chad,  Niger,  Senegal, Volta?. Also known from Guinea, Sierra Leone and Liberia
Size: 
30.5cm. (12¼ins)
Temp:
22-26°C (71-79°F)  
pH.:
6.0 -8.0.
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                                                                                                                                   Factsheet 147 = updated January 9, 2017 , © ScotCat 1997-2016  Go to Top