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Banded knifefish

Gymnotus carapo

Also known as Carapo knifefish, Tuvira

FreshwaterFish
Banded knifefish (Gymnotus carapo)
Naturalist_on_the_River_Amazons_figure_21.png: Unknown authorUnknown author derivative work: Haplochromis (talk) · Public domain

Care at a glance

Temperature
73–82°F (23–28°C)
pH
6.0–7.5
Adult size
15.7 in (40 cm)
Minimum tank
79 gal (300 L)
Temperament
Aggressive
Social behavior
Solitary
Swim level
Bottom
Difficulty
Medium
Breeding
Hard
Rarity
Rare
Origin
Native to slow rivers, floodplains and swamps across much of South America, hiding among submerged roots and leaf litter.
Family
Gymnotidae

Overview

Reaching around 40 cm, it needs at least 300 litres with plenty of caves, wood and dim lighting. Keep it at 23 to 28 C and pH 6.0 to 7.5. It is predatory and territorial, so keep it singly and only with tankmates too large to eat. Feed earthworms, prawns, bloodworm and other meaty foods after dark.

In the wild

The banded knifefish is a South American electric fish with a tapering, knife-like body banded in brown and cream. It swims by rippling a long fin under the body, moving smoothly forward or backward. It is nocturnal and finds its way by generating a weak electric field.

Good to know

Gymnotus carapo produces a weak electric discharge used for navigation and communication in dark, murky water. It commonly reaches around 40 cm, with wild fish occasionally larger. It is an air-gulping predator active mainly at night.

Did you know

The banded knifefish reads its surroundings with a self-generated electric field, so it can hunt and steer in complete darkness.

Where to buy

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…or ask your local fish store.

Appears in

Freshwater fish · Bottom dwellers · Monster fish

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