15 Fascinating Fish That Swim Upside Down

A fish that can swim upside down

Most fish use their swim bladder, a gas-filled sac located in the top part of their body cavity, to control buoyancy.

In case of swim bladder disorder, the fish struggle to maintain their buoyancy and start swimming upside down.

However, the Upside-Down Catfish species are known to swim upside down naturally.

So, let’s learn about these fish in more detail.

15 Fish That Can Swim Upside Down

1. Asian or Burmese Upside Down Catfish

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Scientific Name: Mystus Leucophasis

Mystus Leucophasis is an Asian or Burmese species of upside-down catfish that belongs to the family Bagridae.

This fish is native to the Sittang and other rivers of Myanmar.

It’s known for swimming upside down and never upright. The Burmese upside down catfish can grow up to 12 inches in length.

Adult males have thinner bodies and more petite stature.

In contrast, the fully matured females are longer than the males and have heavier bodies.

The body of an adult Burmese upside down catfish is covered in black color with a few diamond specks along the flanks.

They’re commercially caught for human consumption and for the aquarium industry.

However, avoid keeping these catfish with smaller fish in a community aquarium as they will eat the smaller fish.

2. Polkadot Squeakers

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Scientific Name: Synodontis Angelicus

Synodontis Angelicus is a species of upside-down catfish also known as Angel Squeaker, Polkadot Squeaker, Black Clown Catfish, Pearl Squeaker, or Whitespotted Squeaker.

This fish is native to the warm waters of the Congo basin in the Democratic Republic of Congo and the Republic of Congo in Africa.

It’s known to grow up to an average of 9.8 inches in length. However, there is evidence of it growing up to 22 inches in length.

Polkadot squeakers are grey to dark violet with reddish-yellow to bark brown-red spots on their head, sides, adipose fin, and ventral surface.

This fish is also found in home aquariums.

The Polkadot squeaker is active mainly during the night.

It’s an omnivore that readily eats smaller-sized live and prepared food.

3. Network Synodontis

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Scientific Name: Synodontis Aterrimus

Synodontis Aterrimus, also known as the Network Synodontis or Network Syno, is a species of upside-down catfish found in the middle part of the Congo Basin in the Democratic Republic of Congo.

The network syno can grow up to 4.5 inches in length.

Generally, a fully grown female fish tends to be slightly larger than a fully grown male fish.

This fish has a large, bony head capsule extending back as far as the front spine of its dorsal fin.

The head has a distinct narrow, bony, external protrusion called the humeral process.

This catfish species is found in the Congo river basin and harvested for human consumption.

In general, this fish is omnivorous and eats insects, algae, gastropod mollusks, bivalve mollusks, crustaceans, sponges, and the eggs of fish in the wild.

4. Giant Upside Down Catfish

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Scientific Name: Synodontis Batensoda

Synodontis Batensoda is also known as Squeaker or Giant Upside Down Catfish.

It can be found in the inland waters across Africa, from Senegal to Ethiopia.

This giant catfish always swims upside down. It can grow up to 20 inches in length and weigh up to 1.5 kilograms.

The giant upside down catfish is silver-green to blue-grey in color with black barbels and a dark underside.

Some of them can be reddish brown.

This fish is docile for its size. It’s a hardy fish and is compatible with even small fish.

However, the other species of aggressive synodontis are known to bully this peaceful fish.

This gentle giant is an omnivore and feeds on plankton, alga, detritus, insect larvae, benthic crustaceans, and mollusks.

5. Bugeye Squeakers

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Scientific Name: Synodontis Contractus

Synodontis Contractus or Bugeye Squeaker is a species of upside-down catfish.

The fish is native to the Congo basin in the Democratic Republic of Congo and the Republic of Congo in Africa.

The bugeye squeaker can grow up to 3.8 inches in length.

This fish has a torpedo-shaped, rounded body that appears to have contracted relative to its height.

It can be found in the aquarium hobby. It requires a dimly lit environment with a soft bottom substrate and rocks.

You also need to install driftwood and twisted roots that offers plenty of hideouts.

Broad-leaved aquatic plants, such as Anubias or Echinodorus, and floating vegetation are also preferred as this fish likes to rest under these at night.

Bugeye squeakers are omnivores and eat live and frozen food, including some vegetable matter.

This fish is non-fussy and will eat what is offered.

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6. False Upside Down Catfish

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Scientific Name: Synodontis Nigrita

False Upside Down Catfish or Synodontis Nigrita is a species of upside-down catfish that can be found widely across the waters of Northern Africa.

The false upside down catfish can grow up to 13 inches in length.

Adult females are generally slightly larger than males of the same age.

The body color of this fish is dark brown or olive to black, with round black spots.

Its fins are grey to blackish in color, with the tail fin having black spots or crossbars.

In general, this catfish is omnivorous and eats insects, algae, gastropods, bivalves, crustaceans, sponges, and fish eggs in its natural habitat.

7. Blotched Upside Down Catfish

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Scientific Name: Synodontis Nigriventris

Synodontis Nigriventris, also known as the Blotched Upside Down Catfish, is a freshwater fish species found in the Congo River basin in Central Africa.

The blotched upside down catfish can grow up to 3.8 inches in length.

This fish has adapted Itself to spend most of its time upside-down.

This fish is well suited for aquariums because of its tiny size and peaceful nature.

If you want to enjoy this fish, you should keep it in small groups.

It prefers both prepared and live food, mainly frozen brine shrimp, bloodworms, and aquatic plants.

8. Big Spotted Squeakers

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Scientific Name: Synodontis Alberti

Synodontis Alberti, also known as the Bigeye Squeaker, Bigspotted Squeaker, or High-Fin Synodontis, is an upside-down catfish species native to the Congo Basin in Africa.

This fish can grow up to a length of 6 to 8 inches. It’s grey to brown in color, with the male fish having small dark spots.

In contrast, the spots on the females disappear as they mature.

The big spotted squeaker can be housed with medium-sized fish in community aquariums.

However, this fish is known to bully timid or docile tankmates.

It prefers wood instead of rocks. Aquatic plants can provide cover and encourage it to move around.

However, providing it with a cave or decor for refuge is essential.

This omnivore’s diet includes benthic algae, weeds, insects, and worms.

In captivity, you can feed it sinking catfish pellets and bloodworms to balance its protein requirements.

9. Orangestriped Squeakers

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Scientific Name: Synodontis Flavitaeniatus

The Synodontis Flavitaeniatus is also known as Orangestriped Squeaker, Chocolatestriped Squeaker, Yellowstriped Squeaker, or the Pyjama Syno.

This upside-down catfish is native to the Democratic Repub­lic of the Congo and the Republic of the Congo, where it lives in the lower and central Congolese Basin.

The orangestriped squeaker can grow up to 6 to 8 inches.

Its body is brownish or orange-brown in color and is marked with yellow and dark brown horizontal bands.

The bottom of this fish has small irregular blotches.

This omnivore fish eats flakes, sinking pellets, and small live food.

However, it must not be kept with aggressive fish as it doesn’t compete well for food.

10. Bigeye Squeakers

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Scientific Name: Synodontis Pleurops

Synodontis Pleurops, also known as the Congo Squeaker, Bigeye Squeaker, or the Bug Eyed Synodontis, is a species of upside-down catfish.

This fish inhabits the warm waters in the upper Congo Basin of the Democratic Republic of the Congo, the Republic of the Congo, and Cameroon in Africa.

This squeaker grows between 9 to13 inches in length.

It’s a peaceful and skittish fish but can hold its own if it’s kept with aggressive fish species.

The body of this fish is brown and mottled with a white underside.

There are brown edges on the caudal fin lobes. However, this fish is noted for its large head and eyes.

It’s an omnivore, with more preference for algae and vegetable matter than meat.

11. Two Spot Synodontis

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Scientific Name: Synodontis Nummifer

Synodontis Nummifer, or Two Spot Synodontis, is an upside-down catfish species that inhabit the waters of the Congo Basin of Cameroon, the Democratic Republic of the Congo, and the Republic of the Congo.

The two spot synodontis can grow between 7 to 8 inches in length.

The name nummifer is derived from Latin, which means bearing a coin, referring to the large spots on both sides.

The body of this fish is olive-colored on the back side and whitish on the underside.

This fish has a significant round black mark on each side above its lateral line.

12. Coas Synodontis

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Scientific Name: Synodontis Obesus

The Coas Synodontis or Synodontis Obesus is a species of upside-down catfish native to the coastal drainages of Cameroon, Ghana, Nigeria, and Togo.

Coas synodontis can grow up to 10 inches in length.

In general, the female fish grows slightly larger than the male fish of the same age.

The base body color of this fish is brown with dark spots or dots, which are more distinct in younger fish.

On the contrary, the young ones have white fins with round black spots.

Coas synodontis is an omnivore that eats insects, algae, gastropods, bivalves, crustaceans, sponges, and fish eggs in its natural environment.

13. Black Synodontis

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Scientific Name: Synodontis Haugi

Synodontis Haugi, known as the Black Synodontis, is an upside-down catfish species native to Gabon.

This fish inhabits the warm waters of the Ogowe river basin.

In its natural habitat, the black synodontis grows between 10 to 12 inches in length.

As an omnivore, it eats both plant matter and small invertebrates.

This fish has a uniform brown color or brown color with indistinct dark spots on the body and fins.

On the other hand, young ones display large dark brown spots on their sides.

14. Scissortail Synodontis

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Scientific Name: Synodontis Soloni

Synodontis Soloni, or the Scissortail Synodontis, is an upside-down catfish species found in the Ubangi river of the Democratic Republic of the Congo.

The scissortail synodontis can grow up to 6 inches in length.

In general, the female fish grows slightly larger than the male fish of the same age.

This fish is olive-grey on the back and marbled with brown and white on the underside.

The dorsal and caudal fins of this fish have round brown spots.

It’s found in the lower Congo River basin and harvested for human consumption.

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15. Mustard Catfish

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Scientific Name: Synodontis Albolineatus

The Mustard Catfish, Mustard Squeaker, or Synodontis Albolineatus, is a species of upside-down catfish native to the Ntem and Ivindo rivers in Gabon and Cameroon.

In its natural habitat, the mustard catfish grows between 4 to 7 inches in length.

As an omnivore, it eats both plant matter and small invertebrates.

The body of this fish has a dark brown to black color with turquoise-colored marbles or spotting; spots are smaller on its head.