The upside-down catfish got its name because it swims upside down. Their unusual behavior gives any freshwater tank a unique aesthetic.
They are a peaceful species. Yet, upside-down catfish are best in freshwater tanks with species of the same size.
What Is The Upside Down Catfish?
It might be alarming to see a catfish upside down, but it’s normal, even though scientists aren’t sure how they do it.
Researchers studied their bodies but didn’t find anything out of the ordinary. The swim bladder and balancing organ of the ear are the same as that of other catfish species.
Still, K Ohnishi et. al. performed studies that suggest “Synodontis nigriventris has a high ability to keep upside-down posture and the gravity sensation in this catfish is likely to contribute to its different postural control from that of many other fishes.”
Their body mechanisms remain a mystery. But, it’s no secret that the upside-down positioning is advantageous. Lauren Chapman is a biology professor at McGill University. She says, “The upside-down catfish seems to have a whole suite of adaptations that make life at the surface more tenable.”
They Swim Faster Upside-Down
The upside-down cat can swim right-side up, but they swim faster upside-down.
Robert Blake was a biology professor at the University of British Columbia. He found that deeper underwater, swimming upside-down didn’t offer any advantages.
But, near the surface, swimming upside-down produces less drag, making swimming easier.
They Use Barbels To Navigate
They have sensory organs called barbels to help them navigate murky waters. Their three sets of barbels accompany two large eyes, a forked tail, and a large adipose fin.
Their Fins & Color Offer Protection
Their pectoral fins have ridges of sharp spines that protect them from predators. If something tries to eat them, the catfish becomes lodged in their mouth.
Their bodies are light brown with darker brown splotches. But, the underside of their body is darker than the top of their body.
In most fish, the top of the body is darker to keep them camouflaged at the surface. For the same reason, the underside of the upside-down catfish’s body is darker.
- Common Names: Upside-down catfish, blotched upside-down catfish
- Scientific Name: Synodontis nigriventris
- Origin: Central Africa from Kinshasa to Basonga
- Upside-Down Catfish Size (Length): 3-4 in (7.6-10.2 cm)
- Aquarium Size: 30+ gallons
- Temperament: Peaceful
- Ease of Care: Easy
Habitat
The upside-down cat is native to Central Africa. It lives in the Central Congo River basin from Kinshasa to Basonga. Smaller populations of the fish also live in Cameroon.
The catfish prefer staying close to the banks of the rivers where it hides among the vegetation.
Behavior & Temperament
These upside-down fish are a schooling species that needs to be with a small group of its own kind. Be sure to keep at least 3-4 of these fish in your tank if you want them to be more active. When kept alone, they become stressed and hide more.
Upside-Down Catfish Care
Upside-down catfish are hardy and not particular about their water quality. Still, you should provide them with water parameters that suit them best.
Native to Africa, they are tropical fish that prefer temperatures between 72 to 79 F (22 to 26 C). The pH should be between 6-7.5, and the water hardness should be between 4-15 dGH.
Water Flow
They are native to river habitats with strong flow, so you’ll need to replicate that in their tank. You can buy a powerhead to provide them with a strong enough flow.
A strong current helps with swimming and gives your fish oxygen. Upside-down catfish need higher levels of oxygen than other fish. So, a tank without enough flow will be detrimental to their health.
Upside-Down Catfish Tank Size & Decorations
Upside-down catfish are moderately-sized fish that need plenty of room to swim. You should provide them with at least 30 gallons.
Because they are shy fish, you’ll want to provide them with plenty of places to hide. In the wild, they prefer to spend most of their time amongst the dense vegetation, so it’s good to replicate that.
Buy thick, live plants if you can, like hornwort or anacharis. You should also buy broad-leafed plants like anubius. The fish like to graze on the underside of the leaves.
They also like rocks and driftwood to hide in. Since they love flow, aim to place any hiding spots within the current’s stream.
Diet
Most catfish are bottom-feeders. But, the upside-down catfish prefer to eat off the water’s surface. The positioning of their body makes it easy to graze the surface of the water and the underside of plants.
In the wild, they mostly feed on insects that sit at the surface of the water. They also look for insects, worms, and other tiny organisms on the underside of rocks and wood.
They are omnivores, so they will feed on plant matter and algae if it’s available. But, it doesn’t make up the main part of their diet.
It’s easy to replicate their natural diet in the home aquarium since they are surface feeders. Provide them with insect larvae, like mosquito larvae. You can also offer them freeze-dried, frozen, or live bloodworms or blackworms.
You can offer sinking bottom-feeder pellets as well. It’s not as common for them to eat food from the substrate, but they will.
Upside-Down Catfish Tank Mates
Upside-down catfish are gentle and timid. So, they make good tank mates for most freshwater community tanks.
They are peaceful fish, but they are opportunistic and will eat fish small enough to fit in their mouth. So, avoid fish that are too small.
You should also avoid fish that are too active or aggressive as they will stress out your catfish.
Large fish may try to eat your catfish. If this happens, the upside-down catfish will use its spines to defend itself. Those spines become lodged in the larger fish’s throat and cause serious damage.
Fish who make good upside-down catfish tank mates include:
- Dwarf Cichlids (Apistogramma)
- Small elephant fish
- African butterfly fish
- Congo tetra
How Does the Upside Down Catfish Compare To Other Catfish?
Are you not sure if an upside-down catfish is right for your aquarium? See how they compare to other common freshwater species.
| Upside Down Catfish | Cory Catfish | Asian Stone Catfish | Glass Catfish | Pictus Catfish | Bumblebee Catfish | |
| Temperament | Shy & Peaceful | Shy & Peaceful | Shy & Peaceful | Peaceful | Semi-Aggressive | Shy & Peaceful |
| Preferred Habitat | Rocks & Live Plants | Rocks & Live Plants | Sandy Substrate | Mid-Water Dwellers | Rocks & Live Plants | Rocky Substrate |
| Lifespan | 5 Years | 5+ Years | 5 Years | 8 Years | 8-10 Years | 4-5 Years |
| Size | 3-4 Inches | 1-2.5 Inches | 1.3 Inches | 4-6 Inches | 5 Inches | 3 Inches |
Conclusion
Upside-down catfish are popular for their unique swimming habits and gentle qualities. They make great companions for gentle species of a similar size. They may eat smaller fish, and their sharp spines can hurt larger fish who try to eat them. So, take caution when choosing tankmates.
Provide them with plenty of flow, lush vegetation, and rocks to hide and scavenge. Doing so will provide you with the best habitat and a nicely decorated tank.
FAQs
Yes, upside-down catfish are nocturnal. They spend most of the day hiding under rocks and driftwood. If you watch them at night, you will be more likely to see them swim around.
Upside-down catfish mostly feed on insects and other meaty foods. Still, they eat plant matter and algae when it’s available. Just don’t rely on them to keep your tank free from algae.
There is no research proving that upside-down catfish play dead. But, some owners say they’ve observed it.
No, upside-down catfish are peaceful and get along well with other fish. But, they are opportunistic and will eat fish smaller than them.
