#gymnotiformes

[fish-facing-forward]

Electrophorus electricus

Electric eel

Image source

Status: Least concern

Distribution: Freshwater habitats of northern South America

[herpsandbirds]

Barred or Centipede Knifefish (Steatogenys elegans), family Rhamphichthyidae, order Gymnotiformes, found in freshwater habitats in much of tropical South America

photos: The Wet Spot Tropical Fish, Aquarium Glaser,

[bestanimal]

Round 3 - Actinopterygii - Gymnotiformes

(Sources - 1, 2, 3, 4)

Order: Gymnotiformes

Common Name: “Neotropical knifefish”

Families: 5 - Apteronotidae (“ghost knifefishes”), Sternopygidae (“glass knifefishes”), Gymnotidae (“naked-back knifefishes” and “electric eels”), Hypopomidae (“bluntnose knifefishes”), and Rhamphichthyidae (“sand knifefishes”)

Anatomy: long bodies with elongated anal fin; tapering tails; scaleless; have electric organs capable of producing electric fields to detect prey, for navigation, communication, or attack and defense

Diet: bottom-dwelling invertebrates, fish, caecilians

Habitat/Range: rivers and streams throughout the humid Neotropics, ranging from southern Mexico to northern Argentina; almost exclusively in fresh water (may visit brackish water to feed)

Evolved in: Late Jurassic

(source)

Do you have a favorite in Gymnotiformes?

One or more of my favorite animals is in Gymnotiformes

I love at least one or more of these animals

I like at least one or more of these animals

I am neutral about all of these animals

I dislike all of these animals

Voting ended onJun 30, 2025

Propaganda under the cut:

The electric organs of most Gymnotiformes produce tiny discharges of just a few millivolts, far too weak to cause any harm to other fish. Instead, they are used to help navigate murky environments, detect prey within sediment, and send signals between fish of the same species. In addition to this low-level field, the electric eels (genus Electrophorus) (image 2) also have the capability to produce much more powerful discharges to stun prey, and shock predators.

Their electrical capabilities of electric eels were first studied in 1775, contributing to the invention of the electric battery in 1800.

Electric eels will continue growing for as long as they live, adding more vertebrae to their spinal column. Some captive individuals have lived for over 20 years.

Vari’s Electric Eel (Electrophorus varii) exhibits greater parental care than the other two species of electric eel. The male makes a nest using his saliva, into which the female deposits around 1,200 eggs for external fertilisation. Spawn hatch seven days later and the mother will keep depositing eggs periodically throughout the breeding season. When they reach 15 mm (0.59 in), the hatched larvae consume any leftover eggs, and after they reach 9 cm (3.5 in) they begin to eat other foods. The male will provide protection for both the young and the nest for up to 4 months.

The Banded Knifefish (Gymnotus carapo) can survive in low-oxygen habitats by breathing air with a modified swim bladder, areas affected by pollution, and for a period on land if its aquatic habitat dries out.

The ghost knifefish species Sternarchogiton nattereri is unique in that its diet consists of freshwater sponges growing on submerged trees, stumps, and other woody debris.

The glass knifefish Eigenmannia vicentespelaea is the only cave-dwelling gymnotiform, and has reduced or absent eyes. As some individuals retain well-developed eyes, this fish may have colonized caves only recently in evolutionary time, and are currently evolving a lack of eyes as an adaptation to cave life.

Neotropical knifefish can lose their tail due to attacks by predators or aggressive encounters other knifefish, but they are capable of regenerating it.

[have-you-seen-this-animal]

My favourite fish the Black Ghost Knifefish? :D

Have you seen the black ghost knifefish (Apteronotus albifrons)?

I have now

Yes, in photos/videos

Yes, irl

I'm not sure

Voting ended onSep 22, 2025

[taxonomytournament]

Taxonomy Tournament: Fish

Gymnotiformes. This order is known as Neotropical knifefish, which have an elongated body and anal fin, and are capable of producing electric fields which they use to detect prey. Members include the electric eel and glass knifefish

Siluriformes. This order is made up of catfish, which have prominent barbels (sensory organs near the mouth) that resemble a cats whiskers.

Which clade of animals is better?

Gymnotiformes

Siluriformes

Show results

Voting ended onFeb 18, 2024

[herpsandbirds]

Electric Eel (Electrophorus electricus), family Gymnotidae, order Gymnotiformes, found in freshwater habitats in northern South America

These predatory fish are able to stun prey using electric shocks of up to 860 volts.

They are not true eels, but are in the same order as neotropical knifefish.

photograph by Oleksandr (Alex) Zakletsky

[fish-facing-forward]

Electrophorus varii

Vari’s Electric Eel

Image source

Status: No IUCN evaluation

Distribution: In the freshwater environments of the Amazon

[herpsandbirds]

Electric Eel (Electrophorus electricus), family Gymnotidae, order Gymnotiformes, found in freshwater habitats in northern South America

These predatory fish are able to stun prey using electric shocks of up to 860 volts.

They are not true eels, but are in the same order as neotropical knifefish.

photograph via: Long Island Aquarium