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Synodontis contractus

Big-nosed Upside-down Catfish

Vinciguerra, 1928Formerly Synodontis contracta

Last revised 2026Edit this page

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Synodontis contractus
Synodontis contractusHippocampus-Bildarchiv

Quick factsEdit

Max size
75mm SL3.0in SL
Aquarium size
60 × 30cm24 × 12in
Temp
22–27°C72–81°F
pH
6.2–7.2
Hardness
3–15dGH

Difficulty5 of 8 measures

Moderate

How the rating is worked out

Space
medium tank
Water
needs a steady pH
Temp
flexible
Diet
unknown
Temperament
unknown
Social
needs to be in a group
Compatibility
unknown

Other demands

Each of these can raise the rating on its own, whatever the measures above say.

Hardiness
hardy

The big-nosed upside-down catfish, Synodontis contractus, is a small Synodontis from the Democratic Republic of Congo and Republic of Congo. Often confused with S. nigriventris, it is easily told apart by its larger eyes and broad mouth and head, and it spends most of its time swimming inverted. It should be kept in groups of at least three or four, and can be delicate and prone to disease when first imported.

Distribution

Edit

Found only in the Democratic Republic of Congo and the Republic of Congo. It occurs in small ponds, backwaters and creeks, often in large numbers.

Found only in the Democratic Republic of Congo and the Republic of Congo. It occurs in small ponds, backwaters and creeks, often in large numbers.

Aquarium size

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Standard length
75mm SL3.0in SL
Aquarium base
60 × 30cm24 × 12in
Volume
~54litres~14US gal

60 ∗ 30 ∗ 30 cm24 ∗ 12 ∗ 12 in

Maintenance

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A dimly lit aquarium with a soft substrate and rocks, pieces of driftwood and twisted roots arranged to form hiding places suits this species. Broad-leaved plants, such as Anubias or Echinodorus and floating vegetation are also recommended, as the fish like to roost under these.

Water conditions

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Temperature
22–27°C72–81°F
pH
6.2–7.2
Hardness
3–15dGH

Temperature: 22 – 27 °C72 – 81 °F

pH: 6.2-7.2

Hardness: 3-15 dH

These recommendations come from this profile’s own figures. They contain affiliate links, so we may earn a commission.

Synodontis are omnivorous and are most unfussy in terms of feeding. Frozen, live and dried foods are all accepted. It also relishes vegetable matter in the form of shelled peas, cucumber etc., which it will rasp at with the teeth in its lower jaw. Unlike most others in the genus, S. contractus will often feed from the surface in its typical inverted style.

Behaviour and compatibility

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One of the most gentle members of the genus, S. contractus can be combined with most peaceful species successfully. The most appropriate tankmates include African tetras, dwarf cichlids such as Pelvicachromis or Anomalochromis and small mormyrids. This species should be maintained in groups of at least 3-4 individuals, as this will give them confidence and encourage them to be seen more often.

Sexual dimorphism

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Cannot be sexed by the genital papilla technique as it is too small, although the same dimorphism is apparent. It is therefore difficult to sex, although adult females are generally plumper than males.

Reproduction

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Has been spawned in aquaria but the eggs did not hatch.

Notes

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Often confused with the similar S. nigriventris, this species is imported infrequently. It is easily distinguished from nigriventris by its larger eyes and broad mouth and head. These features give rise to the common name "Big-nosed upside-down catfish". S. contractus spends the majority of its time swimming in an inverted position and this, along with its exaggerated facial features, make it a characterful and interesting addition to the community aquarium. It is also known as the Bug-eyed Squeaker.

One point that should be noted, is that this species can be quite delicate and susceptible to disease when it is first imported. Extra care with regards to water quality should be taken during the acclimatisation period. Once settled, it usually proves quite hardy.

How the name has changed

  1. Renamed from Synodontis contracta to Synodontis contractus.

    2026Eschmeyer's Catalog of Fishes: genera, species, references

Distribution

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