Author: (Linnaeus, 1766)
FBname: Electric eel
Remark: If confirmed as having been actually made available before <i>Gymnotus electricus</i> Linnaeus (1766), <i>Gymnotus tremulus</i> Houttuyn (1764) should be regarded as the senior synonym. However, following Articles 23.9.1 and 23.9.2 of the Code (ICZN, 1999), <i>Gymnotus electricus</i> must be regarded as the valid name, and qualified as a nomen protectum, and <i>Gymnotus tremulus</i> as a nomen oblitum. It seems that both Houttuyn’s (1764) and Linnaeus’ (1766) descriptions were based on previous descriptions by other authors (i.e., primarily, Gronovius and Seba), and that no specimens were actually examined by these authors regarding their proposals of new species. Gronovius’ specimen (or specimens) is currently probably lost, but Seba’s specimen (which apparently have come from the Essequibo river; Seba, 1758, III, p.108, pl. 34, fig. 6) is probably housed in the Rijksmuseum van Natuurlijke Historie, Leiden (Netherlands). That should, then, be considered the remaining name-bearing type for both species above (ICZN, 1999, Article 72.5.6).
Comments: Prefer muddy bottoms and calm waters; frequently found in coastal plains, swamps and creeks but is also found inland where a favorable biotope exist.  Juveniles feed on invertebrates, adults feed on fish and small mammals (Ref. 12225), first-born larvae prey on other eggs and embryos coming from late spawning batches (Ref. 40645).  The electric organ of this species consists of flattened electrocytes, numbering to about hundreds of thousands, connected in series (Ref. 10840; 10011).  Generates two type of electric organ discharges (EODs) from different electric organs which are of myogenic derivation:  1) low-voltage EODs (about 10 V) emitted by the Sach's organ at rates of up to 25 Hz, and 2) high-voltage EODs (about 50-fold) emitted by the main and Hunter's organs at peak rates of up to several hundred Hz.  Low-voltage EOD has been associated with electro location whereas high-voltage EOD has been noted during predatory attacks (Ref. 10011).  An EOD of 500 V was recorded from a 1 m specimen (Ref. 10530), making it a potentially dangerous species.  Incorporation of this species in fish-based house security systems has been suggested (see Ref. 9506).  Also possesses high-frequency sensitive tuberous receptors patchily distributed over the body that seems useful for hunting other gymnotiforms (Ref. 10583).  A nocturnal species; captive specimens showed higher low-voltage EOD activity during the night compared to daytime (Ref. 10011).  This cycle seems to be free-running (internally controlled) (Ref. 10829).  Probably a fractional spawner; fecundity count was17,000 eggs (Ref. 10630).  An obligatory air breather (Ref. 10011) and can withstand poorly oxygenated water (Ref. 26457).  Used in experimental studies.