The upside down catfish (Synodontis nigriventris) is a small catfish found in the Democratic Republic of Congo, Republic of Congo, and Cameroon where it inhabits densely vegetated areas of river banks. This fish grows to an adult size of up to 4 inches long. Sexually mature males are normally thinner bodied and darker in color than females.
The upside down catfish spends up to 90% of its time in the inverted position and there have been several scientific studies conducted regarding its postural control. It was discovered that neither the swim bladder or inner ear mechanics (used for balance) were different than those in other fish. Changes in gravity also appear not to affect the fish. However, what was found, is that the relationship between the central nervous system and the inner ear organ is somewhat unique, and has a self-regulating capacity which essentially “resets” whenever the fish tips beyond 22°, allowing the fish to always remain stable.
The upside down catfish should be maintained in an aquarium 29 gallons or larger. A dimly lit aquarium with a soft sandy substrate (CS7538) and rocks, pieces of driftwood (ZM2000) and twisted roots arranged to form hiding places suits this species well. Broad leaved plants such as Anubias or sword plants and floating vegetation are also recommended as the fish like to roost under these.
The upside down catfish prefers a temperature of 75°F to 82°F, a pH of 6.0 to 7.0, and a hardness of 5 to 20°H. Be sure water is clean and well oxygenated with a moderate flow rate.
The upside down catfish is a generally a peaceful fish suitable for a community aquarium. Good tank mates include most livebearers, danios, rasboras, tetras and peaceful bottom dwellers such as Corydoras or smaller Loricariids. It can also be kept with most commonly available gouramis and dwarf cichlids. Upside down catfish enjoy the company of their own kind and should be kept in groups of at least 3 or 4 individuals to encourage them to be seen more often and simulate more natural behavior.
The upside down catfish is easy to feed in the aquarium and will readily accept prepared foods such as sinking pellets (AL166) and algae wafers (HIK6789), as well as a variety of frozen foods. For maximum color, growth, and health these fish will look their best when given probiotics (AL169) in addition to a balanced diet.