Upside-down catfish

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Synodontis nigriventris, shown here, is commonly confused with species such as Synodontis aterrimus, Synodontis contractus, and Synodontis nigrita, all of which may be sold to aquarists as the "upside-down catfish".

The name upside-down catfish is most commonly used by aquarists to refer to the mochokid catfish Synodontis nigriventris alternately known to ichthyologists as the blotched upsidedown catfish or false upside down catfish .[1] However, a number of other fishes may also be known by this name:

The name 'dwarf upside-down catfish' is also used for small (around 10 cm) species of the catfish genus Synodontis. In the aquarium trade, the name is almost always applied to S. nigriventris or species with which it may be confused, such as S. aterrima, S. contracta, and juvenile S. nigrita (adults of which are around 20 cm so are not "dwarf" species at all).[5][6][7]

As its common name implies, the upside-down catfish will swim upside down. One theory accounts for this unusual behavior as a feeding strategy. In the wild, it often grazes on the undersides of submerged branches and logs, and swimming upside down makes these areas more accessible.[8] A different theory suggests swimming upside-down makes aquatic surface respiration more efficient.[9]


  1. ^ "Common Names of Synodontis nigriventris". Retrieved 2007-06-18. 
  2. ^ David Sands (1986). A Fishkeeper's Guide to African and Asian Catfishes, pp 40-41. Salamander Books ISBN 0-86101-211-9.
  3. ^ "Synodontis contractus". Retrieved 2007-06-18. 
  4. ^ "Common Names of Synodontis angelicus". Retrieved 2007-06-18. 
  5. ^ a b David Sands (1986). A Fishkeeper's Guide to African and Asian Catfishes, p 58. Salamander Books ISBN 0-86101-211-9.
  6. ^ a b "Synodontis contractus". Retrieved 2007-06-18. 
  7. ^ a b David Sands (1986). A Fishkeeper's Guide to African and Asian Catfishes, p. 67. Salamander Books ISBN 0-86101-211-9.
  8. ^ "Upside-Down Catfish". Retrieved 2009-03-15. 
  9. ^ Lauren J. Chapman, Les Kaufman and Colin A. Chapman (1994). "Why Swim Upside Down?: A Comparative Study of Two Mochokid Catfishes", Copeia, Vol. 1994(1), p. 130-135