Upside-down catfish (lat. Synodontis nigriventris) belongs to Mochokidae family. The distinctive feature of the family representatives is that they swim upside-down which is quite normal for them. They spend up to 90% of time swimming this way.
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Habitat in the wild
The upside-down catfish belongs to the family Mochokidae. This family is also commonly referred to as the “squeakers” or “upside-down catfish” family. Mochokidae is a family of small to medium-sized catfish that are primarily found in Africa, especially in freshwater habitats such as rivers, streams, and lakes. Upside-down catfish (Synodontis nigriventris) are one of the notable members of this family, known for their unique behavior of swimming upside down and their peaceful nature in the aquarium.
The upside down catfish is spread in the midstream of Congo River basin including Pool Malebo, Kasai River and Ubangi River. Also there is information that the fish was encountered in Kouilou Department of the Republic of the Congo. It was artificially introduced to Philippines.
The catfish feeds mainly at night. In the wild it basically feeds on insects (fallen on the water surface), crustaceans and plant food. But it has an inferior mouth, that’s why quite often the fish has to swim upside-down to gather the food from the water surface. This is how the fish got its name.
Description
Lifespan
The lifespan of upside-down catfish (Synodontis nigriventris) can vary based on factors such as care, diet, water quality, and genetics. In well-maintained aquarium conditions, upside-down catfish can typically live for about 5 to 10 years. Providing them with a suitable environment that mimics their natural habitat and proper feeding can contribute to their overall health and longevity. Regular water changes, a balanced diet, and a stress-free environment are essential for maximizing the lifespan of these catfish in captivity.
Size
Upside-down catfish are relatively small catfish species. They typically grow to a size of about 3 to 4 inches (7.5 to 10 cm) in length when fully mature. This makes them well-suited for smaller aquariums or community tanks. Their small size, unique behavior of swimming upside down, and peaceful nature make them popular choices among aquarium enthusiasts. Providing them with proper care, a suitable tank size, and a compatible tank environment will ensure they thrive and exhibit their distinctive behavior.
Body
The body is short and a bit flattened from sides. The back is more gibbose, than the abdomen; the eyes are large, the inferior mouth has three pairs of barbels, the tail fin is bilobular. The dorsal is of triangular shape and has a large first ray; the fish has large fatty fin.
The body coloring is greige with black-brown spots scattered over the body and fins. Unlike other fishes who have their back darker than the abdomen (which is necessary to protect the fish from aggression of other fishes or birds), the catfish have darker abdomen and a bit lighter colored back.
Swimming upside-down
Such a distinctive feature appeared because almost 90% of its time spends swimming upside-down. Besides, considering the fact that upside down catfish gathers the food from water surface, it is very important for the fish to keep an eye on what is going on in the lower water layers. This is why this position of its body appears to be the most efficient in this case.
There are quite a lot of special scientific studies devoted to the fish swimming peculiarities. Young catfish swim with their abdomen down like most of other fishes, they start swimming upside-down only in two months after their birth.
The adult upside down catfish prefers swimming upside-down in the bottom water layers; at that this way they swim faster. While swimming with its abdomen up the fish can feed by catching the food from water surface.
Studies of gravitation influence on this catfish showed that it has a high ability to keep its body upside-down and the gravitation is more likely to help it and this indicates that the fish controls its body position in the way that differs from other fishes.
This way of swimming is more energy consuming, however it is compensated with more efficient way of getting food from water surface. Swimming probably developed due to the nocturnal habits of the fish.
| Characteristic | Description |
|---|---|
| Scientific Name | Synodontis nigriventris |
| Family | Mochokidae (Squeakers or Upside-down Catfish family) |
| Origin | West and Central Africa, mainly in Congo Basin |
| Size | 3 to 4 inches (7.5 to 10 cm) at maturity |
| Lifespan | 5 to 10 years in well-maintained aquarium conditions |
| Behavior | Known for swimming upside down |
| Temperament | Peaceful and suitable for community tanks |
| Diet | Omnivorous, feeds on small invertebrates and plant matter |
| Tank Size | Suitable for smaller aquariums (20 gallons or more) |
| Water Parameters | Prefers clean, well-oxygenated water with stable pH |
| Habitat and Range | Found in slow-moving waters with vegetation |
| Compatibility | Generally compatible with other peaceful fish species |
Difficulties in keeping
Upside-down catfish in general is a peaceful and calm fish, but it may show territory dependence and fight with the species of its kind and eat small tank dwellers, whose size allows to eat them. If you put enough of shelters into the tank, you don’t have to worry about the fights. This catfish is more active during the night, this is when it goes to swim and look for food.
Keeping in a tank
It is quite difficult to catch this catfish with a dip net and it is even harder to get it out of the latter safe and sound. The thing is that it spreads its fins with spines wide and gets stuck in the dip net, but if you carefully put it together with the net into another volume, it will easily unhook and swim away.
To avoid all the above mentioned it is recommended to use some plastic container to catch the fish.
Tank size
The tank size for upside-down catfish (Synodontis nigriventris) will depend on various factors, including the number of fish you plan to keep, the overall tank setup, and the other inhabitants in the tank. However, a general guideline is to provide a tank with a minimum size of 20 to 30 gallons for a small group of upside-down catfish.
Since these catfish can grow to around 3 to 4 inches (7.5 to 10 cm) in length and prefer to live in groups, it’s important to provide enough space for them to swim comfortably and establish their territories. A larger tank can also help maintain stable water parameters, which is beneficial for the health of the fish.
Keep in mind that if you plan to keep other fish species in the same tank, you should consider their size, behavior, and compatibility. Avoid overcrowding the tank, as it can lead to stress, poor water quality, and territorial disputes.
As always, providing proper filtration, regular water changes, hiding spots, and suitable tank decorations that mimic their natural habitat will contribute to the well-being of the upside-down catfish and the overall success of your aquarium.
Tank decor
Since fish doesn’t have coarse scales and its barbels are very sensitive, there shouldn’t be any sharp objects in a tank where the fish dwells. Sand or pebbles are good bottom substrate for such a tank. You may put some tank plants into it, though larger fishes may damage them and in this case it’s better to use large plants with coarse leaves.
It should have tank plants and shelters (caves, snags, castles, coco nut shells etc.). It is known that catfish becomes active in the evening or at night, it spends the day in shelters and especially likes hiding in empty objects. At that it hides so good, that you can find it only after looking almost all over the tank.
Water parameters
Optimal tank water parameters to keep upside-down catfish are the following:
- Temperature: The ideal temperature range for upside-down catfish is around 75-80°F (24-27°C). This range closely mimics their natural habitat in the Congo Basin of Africa.
- pH: The pH level should be slightly acidic to neutral, ranging from 6.5 to 7.5. Aim for a stable pH to prevent fluctuations.
- Ammonia and Nitrite: These should be kept at zero. High levels of ammonia and nitrite are toxic to fish. Regular water changes and proper filtration are essential to maintain these levels.
- Nitrate: Nitrate levels should be kept low, ideally below 20 ppm. Regular water changes help keep nitrate levels in check.
- Hardness: The water hardness should be moderate. Aim for a general hardness (GH) of 5-12 dGH and a carbonate hardness (KH) of 3-8 dKH.
- Filtration: A good quality aquarium filter is essential to maintain water quality. Make sure the filter is appropriately sized for the tank and is efficient in mechanical and biological filtration.
- Aeration: Providing adequate oxygenation is important, especially if you have a well-stocked tank. Upside-down catfish, like many fish, benefit from well-oxygenated water.
Remember, it’s crucial to monitor these parameters regularly, especially when setting up a new aquarium or introducing new fish. Consistent water quality checks and proper maintenance will help ensure a healthy and comfortable environment for your upside-down catfish and other tank inhabitants.
Diet
Upside-down catfish are omnivorous, which means they eat a combination of animal and plant matter. In their natural habitat, they primarily feed on small invertebrates, insect larvae, crustaceans, and detritus found in the substrate. In the aquarium, it’s important to replicate their natural diet to ensure their health and well-being. Here’s a diet guide for upside-down catfish:
- High-Quality Pellets: Provide high-quality sinking pellets specifically formulated for bottom-dwelling fish. Look for pellets that contain a balanced mix of protein and plant-based ingredients.
- Live and Frozen Foods: Upside-down catfish will appreciate live or frozen foods like brine shrimp, bloodworms, daphnia, and small crustaceans. These foods mimic their natural diet and provide essential nutrients.
- Bottom Feeder Tablets: Use specialized bottom feeder tablets that are designed to sink and provide a complete diet for bottom-dwelling fish. These often contain a mix of animal and plant-based ingredients.
- Feeding Frequency: Feed your upside-down catfish small portions multiple times a day. They’re generally not aggressive feeders, so it’s essential to ensure the food reaches them before other fish in the tank consume it.
- Observation: Observe their eating behavior to make sure they’re getting enough food without overfeeding. Remove any uneaten food after a few minutes to maintain water quality.
Remember that individual fish may have preferences, so it’s a good idea to offer a variety of foods to meet their dietary needs. A balanced diet is essential for their health, growth, and overall well-being.
Tank mates
It is one of the most peaceful representatives of its kind. The fish can dwell together with majority of not aggressive species, but not with predators. Don’t keep them with small fishes that they can swallow, since at night catfish will hunt them for sure.
Here are some suitable tank mates for upside-down catfish:
- Medium-sized Tetras: Species like glowlight tetras can coexist peacefully with upside-down catfish. They are active mid-level swimmers and won’t compete for the same space.
- Other Peaceful Bottom Dwellers: Corydoras catfish are excellent companions for upside-down catfish. They occupy the bottom of the tank and have similar peaceful temperaments.
- Gouramis: Many peaceful gourami species, such as dwarf gouramis and honey gouramis, can be suitable tank mates. Gouramis typically inhabit the upper-middle water column, reducing competition for territory.
- Small Plecos: If you choose a smaller pleco species, like the bristlenose pleco (Ancistrus spp.), they can be compatible tank mates. Make sure the pleco species you select doesn’t grow too large for your tank.
- Peaceful Dwarf Cichlids: Some dwarf cichlid species, like German blue rams, can be compatible as long as the tank is adequately sized and well-aquascaped to provide hiding spots.
Remember to consider the size of your tank, water parameters, and the number of fish when selecting tank mates. Always monitor the interactions among the fish and be prepared to make adjustments if any aggression or compatibility issues arise. Providing plenty of hiding spots and territories for the different fish can help reduce stress and promote a peaceful coexistence.
Gender differences: male vs female
Distinguishing between male and female upside-down catfish (Synodontis nigriventris) can be challenging, especially when they are young. However, as they mature, there are a few subtle differences that can help differentiate between the sexes. Keep in mind that these differences might not be easily noticeable until the fish are sexually mature, which is typically reached at around 2 to 3 inches in length.
Here are some potential differences between male and female upside-down catfish:
- Size and Body Shape: In some cases, mature female upside-down catfish might have a slightly rounder and fuller body compared to males. Males might appear slightly more streamlined.
- Papilla: The genital papilla is a small, fleshy projection located just behind the vent (anus) of the fish. In mature females, the papilla might appear rounder and slightly more pronounced, while in males, it may be smaller and more pointed.
- Behavior during Breeding: During breeding season, males might exhibit more territorial and aggressive behavior as they compete for the attention of females. Females might be seen preparing spawning sites and cleaning surfaces.
- Egg Laying Behavior: Female upside-down catfish are known to lay their eggs on the undersides of leaves, logs, or other surfaces. If you observe this behavior, it’s likely a female.
It’s important to note that these differences are not always distinct, and it might be challenging to accurately determine the sex of upside-down catfish without professional expertise or experience. If you’re looking to breed upside-down catfish, it’s best to observe their behavior during breeding periods or seek advice from experienced aquarists or fishkeepers.
Breeding
The upside-down catfish becomes reproductive at the age of 2—3 years old. For breeding you will need a tank from 50 liters capacity with various shelters and floating tank plants. Tank water parameters should be the following: temperature 24—27;°C, pH about 7, hardness dH about 10°.
The upside-down catfish very seldom spawns in a tank, that’s why to trigger the spawning process hormones injections are used. Before spawning the couple (1 male and 1 female) are put separately and fed well. The female lays about 450 eggs.
The juveniles start to swim on the 4th day of their life and at first they swim in a usual way, as all fishes do. They start turning upside-down in 7-8 weeks after their birth.