Catfish of the Month Right Arrow April 1999 • Article © Julian Dignall, uploaded April 01, 1999

Upside Down Catfish, Rückenschwimmender Kongowels (Germany), Sortbuget Rygsvømmermalle (Denmark), Vändmal (Sweden) - Synodontis nigriventris   David, 1936

Now here's a catfish that stands out from the multitudinous ranks of its peers. You can't pick up a catfish book without initially reading about how varied and adaptable catfish are, and this month's catfish is one of the reasons why. Here is a very "keep-able" inoffensive fish that has one fascinating feature - it lives its life upside down.

The are only two other species of catfish known to man that share this behaviour, one is the similar but much rarer Synodontis contracta and the beautiful and vicious Asian Upside Down Catfish (USD), Mystus leucophasis. There are other species (amongst them other Synodontis species and some Plecos) that assume the inverted state for varying periods of time, but these 3 are the only ones that spend virtually all their time upside down.

The give away feature is the fishes dark belly. Most fishes have light undersides, a feature developed by them in order to escape detection from predators lurking beneath them. The light, usually white underside against the light water surface makes for a less obvious target. The USD catfish is uniformly patterned even on its belly. The photograph above shows the species in a "normal" swimming position showing the, if anything, lighter back and darker underside - a totally reversal of normal shading.

In the wild these fish are found in huge shoals of several thousand fish. To get the most out of these fish in captivity you have to keep them in good sized shoals - like you would keep Corydoras sp. Although if kept alone they will prosper, they are downright reclusive. Given a fairly shady tank with lots of overhanging retreats a shoal of this species will spend a good deal of the time out and about - much more rewarding for the aquarist, and the fish are obviously more settled too.

The fishes small adult size and peaceful temperament (both in relation to other Synodontis species at least)

suggest it for a place in a medium sized community tank especially when you consider that they also do a very god job of finding food that other inhabitants missed. This feature in addition to their hardy nature also means they can withstand the attentions of some of the more boisterous medium sized Central American Cichlids (Firemouths, Convicts etc.). But beware - these catfish are also very efficient egg eaters!

Copyright information for the images used in this article can be found on the species' full Cat-eLog page.

Jump to next section Cat-eLog Data Sheet
Scientific NameSynodontis nigriventris  David, 1936
Common NamesUpside Down Catfish
Rückenschwimmender Kongowels (Germany), Sortbuget Rygsvømmermalle (Denmark), Vändmal (Sweden)
Type LocalityButa, Zaire.
Pronunciationsin oh don tiss - nig ree VENT riss
EtymologySynodontis: From the Greek syn, meaning together, and odontos, meaning tooth; in reference to the closely-spaced lower jaw teeth. nigri mean dark, ventris meaning belly. Alluding to the reversed counter-shading.
Jump to next section Species Information
Size 100mm or 3.9" SL. Find near, nearer or same sized spp.
IdentificationAll species in the genus Synodontis have a hardened head cap that has attached a process (humeral process) which is situated behind the gill opening and pointed towards the posterior. The dorsal fin and pectoral fins have a hardened first ray which is serrated. Caudal fin is always forked. There is one pair of maxillary barbels, sometimes having membranes and occasionally branched. The two pairs of mandibular barbels are often branched and can have nodes attached. The cone-shaped teeth in the upper jaw are short. S-shaped and movable in the lower jaw. These fish produce audible sounds when disturbed rubbing the base of the pectoral spine against the pectoral girdle.

A common import; although occasionally confused with the similar S. contracta which has a larger head and much larger eyes.
SexingFemale is larger, plumper and with old age more pale.
Jump to next section Habitat Information
DistributionAfrica: Democratic Republic of the Congo.
African Waters, Congo, Middle Congo (click on these areas to find other species found there)
Show it on a map (Click the map-icon to show/hide map of species distribution)
IUCN Red List StatusLeast Concern
pH6.0 - 7.5
Temperature22.0-28.0°C or 71.6-82.4°F (Show species within this range)
Jump to next section Husbandry Information
FeedingWill eat the vast majority of prepared and live foods.
FurnitureOver hanging structures or tunnels - either rock, wood or large broad leafed plants. These are all to provide shady places of rest while upside down. Choice of substrate is unimportant.
CompatibilityAn ideal catfish for the smaller aquarium. Peaceful with both its conspecifics and other residents. To get the best out of this fish it should be kept in small shoals as you would keep Corydoras.
Suggested TankmatesAny small to medium sized community fish.
BreedingIn the North American Catfish Society Vol. 1 No. 1 Jan. 1996 there appeared an article entitled ''Luck In A Bucket'' by Jay and Mary Ann Angros. The authors keep some of their fishes outdoors in the summer. The catfish were placed in a five gallon bucket full of clay pots and PVC pipe from their regular tank. One author, Jay, took the bucket outside and promptly forgot about it for two days! When the bucket of fish was remembered and checked, the authors found fifty eggs in one piece of PVC. The fish were then brought back inside and placed in a tank that was completely full of crockery and PVC pipes. Sometime later this tank was broken down for cleaning and seven S. nigriventris fry were found. The spawning tank had pH 6.8 and the temperature fluctuated between 78F and 82F. The tank had about an inch of gravel over an under gravel filter. Tankmates included skunk Botia and other Synodontis spp. The fish were fed mainly frozen brine shrimp, bloodworm, and ProGreen (a mixture of green, clams, and shrimp). Based on the account above, it would seem that any attempt at spawning the USD Catfish requires, at a minimum, the following:

A well-rounded high quality diet
Drastic temperature drops to initiate spawning
Soft acidic water
Suitable spawning sites
Jump to next section Further Information
ReferencesRev. Zool. Bot. Afr.v. 28 (no. 3) - pp417
Registered Keepers(1) TP (k: 15), (2) Birger (k: 15), who also notes: "Have added a mature "Zebra Kutu" to my group.", (3) synoguy (k: 6), (4) snowball (k: 6), (5) walkinjay81, (6) caudalis (k: 6), (7) Oliver D. (k: 10), (8) CptnSpaulding, (9) amergim, (10) Travis_Conklin, (11) VirgoWolf, (12) Jackp1ne, (13) Marsdinho, (14) Igowoof, (15) Slimlim, (16) teknikAL (k: 2), (17) k1ttyme0w (k: 3), (18) amcmaster, (19) Gopherboy (k: 3), (20) titch2007 (k: 10), who also notes: "always wanted to keep but never had an appropriate set up for them to be happy!!! yet again bought five, hoping to add another 2-3 and trying to encourage them to spawn also!!! they are very secretive fish, but if mixed with suitable tankmate and fed", (21) GoGoCactus, (22) Dave Rinaldo, (23) unblinded, (24) mouseninja, (25) obik101, (26) lizimal, who also notes: "Dec 08 - 2 others mysteriously vanished, only original UD left. New UD Cats - 03/14/08 - $5 each name: Claude. Zebra kutu colour form. ", (27) Chrysichthys (k: 5), (28) Lightbringer (k: 3), (29) pirate monkey (k: 5), who also notes: "What funny little creatures! they make me smile just thinking about them. I haven't managed to get them to eat from surface yet.", (30) jippo (k: 12), (31) didjman89, (32) LUISGOREY, (33) theonetruepath (k: 8), who also notes: "Three are 'Zebra' form", (34) griffl (p: 4, k: 4), who also notes: "Added second which play together everyday.", "Really cool fish. Had to replace the one I lost.", (35) Plunt, (36) synodontisjack, (37) San (p: 2), (38) loachy_406 (k: 3), who also notes: "i have two dark ones and a 'grey' one. They are now becoming a lot braver and search for food with everyone else when the light is off. They tend to swim 'upside up' when they feed.", (39) Upsidedowner (p: 2), (40) joe.juice13 (k: 3), (41) Mariea, (42) norfolkgarden (p: 2, k: 7), who also notes: "Ecellent personality! Constantly playing in the filter outflow or exploring the tank. Ecellent personality! Constantly playing in the filter outflow or exploring the tank.", (43) nmonks (k: 3), (44) iam1ru12 (k: 5), (45) AimsPink, (46) tjcher, (47) doesdavid (k: 6), (48) Dongjin-Kang, (49) seds (k: 4), (50) smegforbrains, (51) ali12345 (k: 4), (52) unkaface, (53) kiwiplymouth, (54) reneb, (55) fischkringli, (56) synofreak, (57) andy75, (58) Nick44 (k: 3), (59) Mike C (k: 2), (60) ariefputranto, (61) judeblackburn (k: 3), (62) corymkl, (63) badtaz30, (64) Caracal (k: 9), (65) Komolaj1 (k: 3), (66) astinus, (67) naturalart (k: 3), who also notes: "Partly bought them to relax my S.alberti and it did the trick. Now on the search for a female.", (68) elle_1313, (69) ayrtoninst, (70) LowClassCC, (71) pickles4601, (72) Viktor Jarikov, who also notes: "very elusive, fast, very good unfussy eater; true to his name; has not grown much unlike others", (73) Wallace (k: 3), (74) stuart264, (75) oli (k: 4), (76) Bijn (k: 5), (77) d3n2 (k: 2), (78) chubbikins (k: 5), (79) alpha (k: 6), (80) tijani, (81) NC24, (82) fishmanbill (k: 2), (83) Mezel (k: 4), who also notes: "I got 4 of these, read about them for a long time. Just love watching them swim. They get along very well with my feather fins.", (84) N0body Of The Goat (k: 11), who also notes: "Lost the biggest of the group 1/3/2017, she was ~8.5cm SL", (85) ad8, (86) GoldenFeather, (87) Buddiechrist, (88) JamesStuddart (k: 4), (89) arapaimag (k: 8), (90) Draco Spectrum, (91) Starfish42, who also notes: "My oldest fish! Originally had 2, but the other died years ago. Just how long can these live?", (92) TheInfamous, who also notes: "Usually stays around the filter away from the other fish, but very cool.", (93) ilikefishme, (94) GreenSynoMan, (95) Katherine, (96) clydeboy (k: 2), (97) Catfish freak, (98) Bruton, (99) scalvinfish (k: 5), (100) transporter42 (p: 2), (101) jimlaroche83 (k: 3), (102) lasteeves (k: 5), (103) cochito, (104) mamoo (k: 4), (105) wirikwiri, (106) guardianfyre, (107) lazymonsterboy (k: 2), (108) merit, (109) mg7454 (k: 5), who also notes: "I was so happy to find these guys! I love watching them play all day around their favorite pieces of Mopani driftwood (which are standing in the corners of the aquarium). They are somewhat active all day; and at night, when I turn on the lunar LEDs in white & actinic blue, they zip around and play all over the aquarium. They are so much fun! The water parameters are 79 degrees, soft and pH is 6.8. I give them Hikari frozen blood worms every day, and they have some of the Aqueon tropical fish flakes I drop in for all of the fish in the aquarium. They also love Hikari algae wafers, they steal them from my Pleco when he's not right on the wafer!", (110) Sam (k: 5), (111) miguel mitchel (k: 2), (112) dbl_dbl, (113) FerocactusLatispinus (k: 4), who also notes: "R.I.P. Moe, Curly, & Shemp, and Larry. Had them for 4+ years; just now a sudden virulent outbreak of I. multifiliis affected only these fish; they succumbed in less than two days, despite my best efforts.", (114) linuxrulesusa (k: 3), (115) Catfishfingers, (116) rizla75, (117) p44236, (118) Mikey1973 (k: 2), (119) Ecrevince (k: 5), (120) Amneris3 (k: 4), (121) Sean B, (122) Divinehammer, (123) Tamcon83, (124) camillajakobsen93 (k: 3), (125) lilu, who also notes: "Fairly shy, hides in the caves or among the plants during the day. Comes out after dark to eat. Very peaceful.", (126) thecameraguy (k: 2), (127) bekateen, (128) chalamala, (129) mizner13, (130) Mol_PMB (p: 2, k: 7), (131) rcbows (k: 2), (132) Johnny579, (133) thijs, (134) Matturbin, (135) jodilynn (k: 2), who also notes: "Adorable little fish! I forgot what lovely little creatures these were, so much more active and "personable" than my big synos. "Fred" (named by my 11 year old son) immediately began feeding when I got him. Always on the move! Can't wait to move him to our new 40 gallon cube and get him a couple friends! Update: Added "Barney" in March, they are still in the 10 gallon chilling out :) .", (136) Long Barbels, (137) Deb (k: 2), (138) NeilB, (139) Catfishlady, (140) Sugeknight, (141) flatdog, (142) faxling, (143) UDCatfish, (144) Thereinh, (145) Tofslan, (146) Localhobo4u, (147) apo1980, (148) kiwidu21 (k: 4), (149) Corvis (k: 5), (150) Reteos, (151) Rhomadeas, (152) Dimidiata, (153) fishyNZ, (154) ad88 (k: 4), (155) WadeNCreeks, (156) Schall, (157) syorksaquarist (k: 10), who also notes: "Mainly nocturnal and non-confrontational. Live happily with Mochokiella paynei, tetras and small cichlids", (158) TheNativeAquarist (k: 2), (159) thalassophoebe (k: 4), (160) Tocinoyhuevos, (161) protopterus, (162) Flatdog, (163) caninesrock, (164) LIttlewing6was9, who also notes: "Vlad joined my 4 Bristlenose Plecos in my 100 litre 2 weeks ago. He/she is quite shy, preferring to hide in the pvc tube or in the rocks.", (165) L-Cait, (166) angerygrover (p: 2, k: 11), who also notes: "Kept in community with African Riverine Cichlids, Mormyrids and Alestiid Characins", (167) CactusCatfish, (168) Noel.

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Breeding Reports(1) Amneris3 (b: 33).
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Last Update2014 Apr 06 10:01 (species record created: 1999 Apr 01 11:22)

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