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

Article © Julian Dignall, uploaded April 01, 1999.

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.

Down Cat-eLog Data Sheet
Scientific Name Synodontis nigriventris  David, 1936
Common Names Upside Down Catfish
Rückenschwimmender Kongowels (Germany), Sortbuget Rygsvømmermalle (Denmark), Vändmal (Sweden)
Type Locality Buta, Democratic Republic of Congo.
Pronunciation sin oh don tiss - nig ree VENT riss
Etymology According to Cuvier, Synodontis is an "ancient name for an undetermined fish from the Nile". It is apparently not derived, as often reported, from syn-, together and odous, tooth, presumed etymology of the lizardfish genus Synodus and in reference to the closely-spaced lower jaw teeth of both genera. nigri mean dark, ventris meaning belly. Alluding to the reversed counter-shading.
Down Species Information
Size 96mm or 3.8" SL. Find near, nearer or same sized spp.
Identification All 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.
Sexing Female is larger, plumper and with old age more pale.
Down Habitat Information
Distribution Africa: Central Congo basin.
African Waters, Congo, Middle Congo (click on these areas to find other species found there)

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IUCN Red List Category Least Concern, range map and more is available on the IUCN species page. Last assessed 2009.
pH 6.0 - 7.5
Temperature 22.0-28.0°C or 71.6-82.4°F (Show species within this range)
Down Husbandry Information
Feeding Will eat the vast majority of prepared and live foods. User data.
Furniture Over 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.
Compatibility An 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 Tankmates Any small to medium sized community fish.
Breeding In 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
Breeding Reports There is but a single breeding report, read it here.
Down Further Information
Reference Revue de Zoologie et de Botanique Africaines v. 28 (no. 3), pp 417.
Registered Keepers There are 196 registered keepers, view all "my cats" data.
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There are 3 wishes to keep this species, see who wants what.
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There are 37 records of this fish being seen, view them all.
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Last Update 2020 Sep 19 01:46 (species record created: 1999 Apr 01 11:22)

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