Gymnotus pedanopterus

Zebra Knifefish

Classification

Gymnotidae

Distribution

Peru and Brazil.

Habitat

Tends to inhabit sluggish or still waters, and seems to prefer turbid environments. It is also found in the deeper parts of main river channels, and in general is considered a benthic (bottom dwelling) species.

Maximum Standard Length

At least 11.2″ (28cm).

Aquarium SizeTop ↑

48″ x 12″ x 12″ (120cm x 30cm x 30cm) – 108 litres if kept alone as a single specimen. Larger if kept in a community situation.

Maintenance

Decor isn’t critical, although it does appreciate plenty of cover. Large stones and pieces of bogwood, twisted roots, and live plants all look good. It is also much more active under dim conditions, so either use weak lighting or add a layer of floating plants to diffuse the light entering the tank.

Water Conditions

Temperature: 72-82°F (22-28°C)

pH: 6.0-7.0

Hardness: 2-12°H

Diet

Offer it live and frozen foods such as bloodworm, prawns, earthworms, tubifex etc. Dried foods are not usually accepted.

Behaviour and CompatibilityTop ↑

Small fish will be eaten, but it can be combined with other similarly-sized species in a big enough tank. Don’t keep it with anything too boisterous or aggressive though, or it might become withdrawn. Possible tankmates include large, robust cichlids such as Cichla or Geophagus sp., larger Characins, Cyprinids, catfish, Loricariids and other species such as bichirs. It’s very territorial with conspecifics, and a very big tank would be needed to keep more than a single specimen.

Sexual Dimorphism

Unknown.

Reproduction

Unknown.

NotesTop ↑

The genus Gymnotus has undergone considerable taxonomic revision in recent years, with over 20 new species being described since 1994, of which this stunning species is one. It’s still very rare in the hobby and tends to command a high price when available. Like other Gymnotids, it produces a weak electric field using specially-adapted muscle tissue located towards the tail. It also possesses electroreceptors which allow the fish to receive electrical signals. With these the fish can sense the tiniest of movements as the field around it is disturbed, and navigate in total darkness, useful skills when hunting prey or avoiding predators in the dark. What is most fascinating about this adaptation is that the fish also use it to communicate with each other and find partners.

A final point to note is that it’s sensitive to many aquarium medications, particularly those containing copper.