The upside-down catfish (Synodontis nigriventris) is a small catfish with the unique habit of swimming and resting upside-down. These fish spend upwards of 90% of their time in the inverted position and have a reverse colour scheme to most fish – with their belly being darker than the dorsal area. This is to help them camouflage from predators as their belly is exposed to the surface of the water when they hunt insects.
And while many people purchase upside-down catfish for their strange swimming habits, their small size and peaceful nature also make them an ideal choice for community aquariums. In fact, they are a favorite with people who prefer oddball fish in a community setting.
|Life Span:||10 Years|
|Size:||4 inches (10 centimeters)|
|Minimum Tank Size:||20 gallons (75 litres)|
Upside-down catfish are native to the Democratic Republic of the Congo, the Republic of Congo, and Cameroon. They are mostly nocturnal and inhabit heavily vegetated streams, rivers, and marshes, often residing close to the shore.
Upside-down catfish need to be kept in a fairly large aquarium and a 20 gallon (75 litre) aquarium is the minimum recommended tank size. While they can be kept individually in smaller aquariums, it’s best to keep these fish in small groups.
Lighting, Decorations, and Substrate
Any tank containing upside-down catfish should be heavily planted, with plenty of broad-leaved plants like Amazon sword plants. Floating plants also make a good addition to their tank, and water lettuce and Amazon frogbit are both good choices. These catfish seem to enjoy browsing the underside of leaves and floating roots looking for insect larvae.
To help upside-down catfish feel more at home, stones and driftwood should be arranged to create hiding places for them. This helps to reduce stress and should contribute to them exhibiting more natural behavior.
The lighting in the aquarium should be subdued with a soft substrate provided. A sand substrate with smooth rivers rocks is recommended in upside-down catfish tanks.
Upside-down catfish are an undemanding fish and most tanks only require a hang-on-back filter. These filters use both mechanical and biological filtration and have the added benefit of providing much-needed current to an aquarium.
I recommend using a AquaClear Power Filter for upside-down catfish aquariums, as they are incredibly durable and do an excellent job keeping the water in pristine condition. I’ve used AquaClear Power Filters on my fish tanks for years without issue and highly recommend it.
Upside-down catfish are omnivores, preying on insects near the surface, while also consuming crustaceans and plant matter. They primarily feed on mosquito larvae in the wild and providing them with larvae in the home aquarium may help to trigger their breeding.
To provide upside-down catfish with a complete diet, they should be fed a high-quality fish food, along with live or frozen food, and blanched vegetables. While illegal to cultivate in many areas, mosquito larvae remain the preferred food. But upside-down catfish will also accept frozen brine shrimp, blood worms, and blackworms.
When choosing a fish food, I recommend picking one that will provide all their needs and Hikari Micro Wafers do all of that and more. Hikari Micro Wafers are specially formulated for catfish and have ingredients to brighten the fish’s colour. And unlike most other catfish, upside-down catfish feed on the surface, so the slowly sinking Hikari Micro Wafers are perfect for them.
While many fishkeepers claim this is the only species of Synodontis that is relatively easy to breed in the home aquarium, it’s difficult to find much information on the process. However, the rainy season marks the beginning of the breeding season in their natural habitat, and it should be possible to simulate this through large water changes with slightly cooler water. This should help to trigger spawning in the home aquarium.
The females have lighter colouring than the males and a more rounded body, which becomes even rounder when spawning. The female will lay eggs in a depression in the aquarium and the parents will care for their brood.
After hatching, the fry will carry their egg sack for four days and after that time, they can be fed baby brine, microworms, or commercially available fry food. The fry will swim right-side-up until they are seven to eight weeks old, at which time they will start to swim upside down like their parents. The juveniles will form schools until they reach two inches in length.
Known as one of the more peaceful catfish, upside-down catfish do well in most community tank setups. They should always be kept in a group of at least five, as this will reduce their stress and help to bring out their natural behavior.
Some good tankmates for upside-down catfish are tetras, dwarf cichlids, and other peaceful fish like zebra danios and Corydoras catfish.