One of the smallest members of the genus Synodontis, the upside-down catfish is aptly named for its upside-down swimming posture, which makes it easier for it to feed more effortlessly on the water's surface. It is also known as the blotched upside-down catfish because of its spotted appearance. They are an extremely popular species that have been admired for countless centuries; their images have even been found in ancient Egyptian art.
Common Names: Upside-down catfish, blotched upside-down catfish
Scientific Name: Synodontis nigriventris
Adult Size: 4 inches (20 cm)
Life Expectancy: 5 years
|Tank Level||All levels|
|Minimum Tank Size||10 gallon|
|pH||6 to 7.5|
|Hardness||4 to 15 dGH|
|Temperature||72 to 79 F (22 to 26 C)|
Origin and Distribution
This fish originates in Central Africa in the Central Congo River basin from Kinshasa to Basonga. It is also found in Cameroon. It inhabits the densely vegetated areas at and around the banks of rivers.
Although they swim faster when upside down, don't be surprised if they swim right-side-up for periods of time. This is particularly true when they want to graze the bottom of the tank for morsels of food. Upon closer examination of the inner structures of this catfish, scientists found that its swim bladder was normal and there was nothing unusual about the balancing organ of the ear, as it resembles that of other catfish.
Colors and Markings
Considered a dwarf catfish, Synodontis nigriventris reach an adult size of only three to four inches. Like other members of the Mochikidae family, they have large eyes, a large adipose fin, a forked tail, and three pairs of barbels. Their light brown colored body is covered with dark brown blotches of various sizes.
These fish have color-adapted to spend most of their time upside-down. The underside of the body has a darker hue, which is the opposite of fish that swim upright. This reverse coloration serves to camouflage them when they swim upside down at the surface of the water.
Like other catfish, they have sharp fin spines that can cause injuries to fishkeepers or that can become entangled when moving them. Take care to use a very fine mesh net while catching or moving this fish.
Upside-down catfish are good community fish. A peaceful species, they can be combined with many other species successfully. Despite its amicable nature, it is still a carnivore that will eat very small fish. It is best kept in small schools; maintain a group of at least three to four, which will give them confidence and encourage them to come out of hiding.
Do not keep this fish with other fish that are large enough to even attempt to predate upon it. It will erect its spines and become lodged in the predator's throat. For this reason, it is wise never to house this catfish with aggressive fish. The most appropriate tankmates include African tetras, dwarf cichlids, such as pelvicachromis or anomalochromis, and small elephantfish.
Upside-Down Catfish Habitat and Care
Well suited to the aquarium environment, the upside-down catfish is easy to care for. Aquarium temperature is not critical but water should be moderately soft and with a slightly acidic to neutral pH. As they are very sensitive to nitrates, good water conditions are necessary. Frequent partial water changes are needed to keep them healthy.
This catfish also typically requires water that is well-oxygenated, and it prefers a relatively strong current. This can be achieved by using powerheads or a spray bar water return attachment on a canister filter. For shelter, provide hiding places that are situated directly in areas of heavy current.
A well-planted tank is ideal, preferably using broad-leafed plants, as they like to browse the undersides of leaves. Driftwood, rock arches, and rockwork decorations are appropriate. Caves that provide places to hide are recommended. It is quite normal for this fish to hang out and congregate on the underside surfaces of rocks, leaves, and driftwood, so offer multiple underneath surfaces that are big enough to accommodate your whole school at once.
Like most catfish, it tends to hide during the day, becoming active at night and during the dusk hours, so adequate hiding spaces are a must. Use a moonlight lighting fixture to view their night activities.
Upside-Down Catfish Diet and Feeding
In nature, the upside-down catfish feeds primarily on insects at the surface of the water, and it often scavages the undersides of submerged branches and logs for worms, insects, and micro-organisms. Swimming upside-down makes these areas easier to access. Omnivores, they will also graze on the available algae to supplement their diet.
In the aquarium environment, they adapt readily to all types of foods, from dry to live to frozen. Offer some sinking catfish pellets, freeze-dried bloodworms, tubifex, and frozen foods like bloodworms and blackworms. For optimum health, provide a varied diet that includes insect larvae when possible, particularly mosquito larvae. Live foods offered at the surface of the water or below will always be readily accepted. Feed vegetable matter in the form of shelled peas and cucumber even if they clean your aquarium algae.
Females are larger, paler in coloration, and have plumper more rounded bodies, particularly when ready to spawn.
Breeding the Upside-Down Catfish
Only a limited number of successful spawnings have occurred in an aquarium. Upside-down catfish prefer cave spawning. Offer an overturned clay flower pot or two or even some PVC pipe as a possible spawning location. Condition the breeders with live foods. Soften the water and use a water can sprinkler to add colder water to the tank, mimicking the spring rains. This will increase the likelihood of successful breeding.
Eggs will generally be laid on the roof of the cave, and up to 450 eggs may be laid. Unlike South American Corydoras catfish, both parents may be left in the tank after spawning, as they will tend to the brood. The eggs hatch in approximately two to three days and the fry will feed off the yolk sac, which they carry for an additional four days.
Once the yolk sac has been consumed, they will begin eating freshly hatched brine shrimp. They initially swim in the upright position before moving into the typical inverted position. After two months, the fry will begin swimming in the characteristic upside-down way.
More Pet Fish Species and Further Research
If the upside-down catfish appeals to you, and you are interested in some compatible fish for your aquarium, read up on:
Check out additional fish species profiles for more information on other freshwater fish.