 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).As its common name implies, the upside-down catfish will swim upside-down.One theory accounts for this unusual behavior as a feeding strategy.