Tetranematichthys wallacei: how big does it get?

Tetranematichthys wallacei is a driftwood catfish from the upper Rio Negro in Brazil, growing to 8 in SL. It is a recently described species with almost no aquarium record.

What's in the name

Tetranematichthys wallacei — tet-ra-nem-a-TIK-theez wal-AY-see-eye

Tetranematichthys

tetraGreek — four
nemaGreek — thread, barbel
ichthysGreek — fish

wallacei

WallaceLatinised surname — genitive of the surname Wallace, honouring a person of that name

Taxonomy & naming

Tetranematichthys wallacei was described by Vari and Ferraris in 2006 from the upper Rio Negro near São Pedro, mouth of the Igarapé do Ibará, Amazonas, Brazil. It is valid in the family Auchenipteridae.

Morphology

FishBase gives a maximum of 8 in SL. The genus name refers to four barbels. The species is scaleless like other driftwood cats. Colour and meristic details are not recorded in the sources used here.

Habitat

The type locality is the upper Rio Negro, a blackwater system. The FishBase entry records no distribution text, temperature, pH or hardness.

Feeding

Diet is not recorded in the FishBase entry.

Mating

Mating is not recorded. Auchenipterids have internal fertilisation as a family trait, which is not documented specifically for this species.

Breeding

Breeding is not recorded.

In the aquarium

It needs a large tank, dim light, wood to hide in and tankmates too big to swallow. Water values are not recorded; soft, acidic, warm water suits Rio Negro fish in general.

Conservation

The IUCN Red List assessed Tetranematichthys wallacei as Least Concern in 2020. No species-specific threats are listed in the sources used here.

Common questions

Tetranematichthys wallacei: how big does it get?: Up to 8 in standard length (SL).
Tetranematichthys wallacei: where does it come from?: It is recorded from Brazil.

On lists: Soft-water fish · Blackwater fish

Also from the Upper Rio Negro

Sources

Naming authority: Tetranematichthys wallacei in Eschmeyer’s Catalog of Fishes ↗

Last reviewed 2026-10-05.

How to cite

Aquarist Atlas (2026). Tetranematichthys wallacei. Aquarist Atlas.https://www.aquaristatlas.com/catfish/tetranematichthys-wallacei/

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Where it has been recorded

51 georeferenced records (GBIF). Each point is a field observation or museum specimen — pan and zoom to explore where this species turns up. The coordinates come straight from GBIF and are often rounded or tied to the nearest town or river landing, so a dot can sit just beside the actual water rather than in it.

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