Upside-down Catfish
Synodontis nigriventris
Description
The Upside-down Catfish is a unique and interesting species of catfish known for its unusual swimming behavior. As the name suggests, this fish is often seen swimming upside down, with its belly facing the surface of the water. This behavior is a natural characteristic of the species, which has evolved to feed on the surface of the water and forage for food in this unusual orientation. The fish has a robust, somewhat flattened body with a dark, mottled coloration that ranges from brown to black, often with white or lighter patches on the underside, giving it a camouflaged appearance. It has large, barbels on its face that are used to detect food in its environment.
Habitat Origin
Native to the slow-moving rivers and streams of West and Central Africa, particularly in the Congo River Basin. These fish thrive in the clear, warm waters of the Congo River and other surrounding areas, where they are often found in shallow, well-oxygenated waters with plenty of hiding spots, such as rocks, driftwood, and plant cover. They are adapted to slightly acidic to neutral water and prefer environments with moderate water flow.
Aquarium
Ideal Number in Aquarium: At least 3 individuals, as they are social fish and feel more secure in groups.
Favorite Food
The Upside-down Catfish is omnivorous and will accept a wide variety of foods. In captivity, they can be fed high-quality pellets, flake food, and live or frozen foods such as brine shrimp, bloodworms, and daphnia. They are also known to graze on detritus and algae, so providing a varied diet is essential for maintaining their health and vibrant coloration. They are bottom feeders and will spend much of their time scavenging for food, especially in a well-planted or natural aquarium setup.
Behavior:
The Upside-down Catfish is peaceful and social, preferring to be kept in schools of at least three or more individuals. They exhibit unique swimming behavior, often hovering upside down with their bellies facing the surface, a natural behavior that helps them forage for food. This behavior, along with their peaceful nature, makes them an interesting and engaging species to observe in a community tank. While they are generally calm, they can be territorial when it comes to food and hiding spaces, especially in smaller aquariums. These catfish are nocturnal and tend to be more active during the evening and night, when they will swim around the middle to upper parts of the tank.
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Special Care:
Upside-down Catfish are relatively hardy, but they do require stable water conditions to thrive. Regular water changes and good filtration are necessary to maintain water quality. These fish prefer a well-planted tank with plenty of hiding spots, such as rocks, driftwood, and plants, where they can retreat and feel secure. A fine substrate, such as sand, is ideal, as they will often forage along the bottom for food. Because they are nocturnal, they may not be as active during the day but will become more lively and engage in foraging behavior at night.
Compatibility with Other Fish:
Yes, Upside-down Catfish are compatible with many other peaceful species. They can be housed with other peaceful, medium-sized fish, such as tetras, rasboras, cichlids, and catfish. They are also compatible with snails and shrimp. It is important to avoid keeping them with overly aggressive or territorial fish that may bully or stress them. Their peaceful nature makes them a great addition to community aquariums, where they can peacefully coexist with other species while displaying their unique swimming behavior.
Breeding Tank Setup
Establishing a dedicated breeding tank for Upside-down Catfish is highly recommended due to their territorial nature during spawning. A separate tank allows effective management of water parameters and reduces the risk of eggs or fry being preyed upon by other fish. A tank size of approximately 100 liters (26 gallons) is ideal, offering adequate swimming space and facilitating stable water quality. These catfish thrive in slightly acidic to neutral water (pH 6.5–7.5), temperatures of 24°C to 28°C (75°F–82°F), and soft to moderately hard water (5–12 dGH). Employ gentle filtration methods, such as sponge filters or internal filters with moderate water flow, to create a calm aquatic environment. Incorporate fine substrate like sand or smooth gravel, along with rock formations or caves, providing secure hiding places for spawning activities. Moderate to subdued lighting replicates their natural, dimly lit, nocturnal habitats, promoting comfort and stress reduction.
Conditioning for Breeding
Conditioning Upside-down Catfish involves feeding them a diverse, protein-rich diet to enhance breeding readiness. Provide high-quality sinking catfish pellets supplemented with live foods like brine shrimp, bloodworms, daphnia, and frozen foods such as mysis shrimp. Regular, small water changes (approximately 25% weekly) are essential to maintain pristine water quality, supporting overall health and encouraging spawning behavior.
Spawning Process
Upside-down Catfish are egg-layers, exhibiting distinct courtship behaviors where males swim around females with visible displays. Following successful courtship, females deposit around 50 to 100 sticky eggs in secure areas such as caves, beneath rocks, or flat surfaces, with males fertilizing them immediately afterward. Adult catfish do not protect their eggs and may consume them, so promptly removing adults from the breeding tank post-spawning significantly increases egg survival and successful hatching.
Fry Care
Eggs typically hatch within 3 to 5 days, depending on water temperature. Newly hatched fry initially rely on their yolk sacs, gradually becoming free-swimming after a few days. Once actively swimming, feed fry small foods such as infusoria, microscopic algae, or liquid fry foods. After several days, transition them to baby brine shrimp or similarly sized live foods, and as they mature, finely crushed high-quality flakes or specialized pellets can be introduced. Maintain excellent water quality through daily small water changes (about 10–15%), stable temperatures (24°C–28°C), and regular monitoring of ammonia, nitrite, and nitrate levels to ensure healthy fry development.
Important Breeding Notes
Upside-down Catfish typically reach breeding maturity between 1.5 to 2 years of age; waiting until they are fully mature significantly improves breeding success. Males are distinguishable by smaller, slender, elongated bodies, whereas females are larger and rounder, especially when carrying eggs. Minimizing stress is critical: maintain stable water parameters, provide ample hiding spaces like caves and plants, and avoid aggressive or overly active tankmates. Sudden environmental fluctuations or poor water quality can hinder spawning and negatively impact egg and fry survival.