''Synodontis nigriventris'', the blotched upside-down catfish, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

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 upside-down catfish or false upside-down catfish. However, a number ...

native to the

Congo Basin The Congo Basin () is the sedimentary basin of the Congo River. The Congo Basin is located in Central Africa, in a region known as west equatorial Africa. The Congo Basin region is sometimes known simply as the Congo. It contains some of the larg ...

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

, the

Democratic Republic of the Congo The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo (the last ambiguously also referring to the neighbouring Republic of the Congo), is a country in Central Africa. By land area, it is t ...

and the

Republic of the Congo The Republic of the Congo, also known as Congo-Brazzaville, the Congo Republic or simply the Congo (the last ambiguously also referring to the neighbouring Democratic Republic of the Congo), is a country located on the western coast of Central ...

Appearance and anatomy

Blotched upside-down catfish are small, reaching a maximum of SL. Like other members of the family Mochokidae, they have large eyes, a large dorsal fin and three pair of barbels. These fish are adapted to spend most of their time upside-down. This is reflected in the fish's pigmentation – their bellies are darker than their backs, a form of

countershading Countershading, or Thayer's law, is a method of camouflage in which animal coloration, an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptile ...

. These fish have lighter colors on the top of their bodies and darker colors below used for

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

. The lighter colors on the top of them make it harder for

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s to see the fish when looking up toward the sky but only when the fish are swimming upside-down.

Ecology and behaviour

''Synodontis nigriventris'' are mostly

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

, and feed on

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s, and plant matter. These fish lay eggs. The young fish do not swim upside-down until they are about two months old. Adults swim and rest upside down in the water. They swim faster when upside down, and are more likely to be upside down around objects or at the water bottom. The more objects around the fish, the more they tend to swim upside down. When close to an object, the fish puts its

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

side closest to the object. It rarely swims in the middle of the water, preferring to swim either at the bottom or at the surface. By swimming upside down when it feeds, it can readily catch prey at the surface from beneath.

In the aquarium

The blotched upside-down catfish is well suited to aquariums because of its small size (typically 9 or 10 cm or less) and peaceful demeanor.

References

External links

{{Taxonbar, from=Q1543723 nigriventris Freshwater fish of Africa Fish of Cameroon Fish of the Democratic Republic of the Congo Fish of the Republic of the Congo Fish described in 1936

Appearance and anatomy

Ecology and behaviour

In the aquarium

See also

References

External links