Photo by Matthew Inabinett, CC BY · source · credits
1 kinds · tap one for a closer look
Shy, nocturnal; needs soft sand and hiding places.
367 species in our list are a good match.
Shy, nocturnal; needs soft sand and hiding places.
Frozen bloodworms, worms.
Tap a food to see what it is.
Cannot be reliably sexed from outside; some sources suggest the anal fin shape differs, and the sexes differ in their electric signals.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Rarely bred in captivity ·
Never bred in captivity; all aquarium fish are wild-caught.
Adults.
Large tank.
Unknown.
Rare.
Brine shrimp.
Uses weak electric pulses from an organ in its tail to find worms and navigate in the dark. Its brain uses about 60% of its body's oxygen, the highest brain-to-body oxygen-use ratio known in any vertebrate.
Albert Günther described the elephantnose fish in 1862 and honoured Wilhelm Peters in its name. It produces a weak electric field to sense its surroundings and communicate in murky water. Its 'trunk' is an extended chin used to probe for worms and insect larvae.
First described by Albert Günther in 1862. Named for Named after German zoologist Wilhelm Peters.
16 facts checked with sources
Valid name Gnathonemus petersii (Günther, 1862); synonyms include Mormyrus petersii and G. brevicaudatus (Wikipedia). All aquarium fish are wild-caught (never bred in captivity), so other mormyrids are sometimes mixed into shipments; check the fish's chin 'trunk' (Schnauzenorgan). No recent renaming found.
FishBase: Gnathonemus petersii summaryLegacy has no family. Order Osteoglossiformes.
FishBase: Gnathonemus petersii summarySeriously Fish 22.5 cm SL; Wikipedia average 23-25 cm. FishBase's 35 cm SL is a wild maximum.
Seriously Fish: Gnathonemus petersii · Wikipedia: Peters's elephantnose fish (cites Nilsson 1996, J. Exp. Biol. 199(3): 603-607) · FishBase: Gnathonemus petersii summaryInside both ranges.
Seriously Fish: Gnathonemus petersii · FishBase: Gnathonemus petersii summaryExact match to Seriously Fish.
Seriously Fish: Gnathonemus petersii · FishBase: Gnathonemus petersii summaryLegacy has no hardness. Seriously Fish 5-15; FishBase 5-19.
Seriously Fish: Gnathonemus petersii · FishBase: Gnathonemus petersii summary120 x 45 x 45 cm = 243,000 cm³ = 243 L, which Seriously Fish calls 'just about acceptable'; legacy 250 L is rounding. A bigger tank is needed for the recommended group of 5+ (FishBase says a tank of at least 150 cm length).
Seriously Fish: Gnathonemus petersiiPairs or small groups lead to the strongest fish bullying the weaker. FishBase also advises groups of 5 or more.
Seriously Fish: Gnathonemus petersiiOnly source is Wikipedia, which does not cite a primary source for this; treat as weakly sourced.
Wikipedia: Peters's elephantnose fish (cites Nilsson 1996, J. Exp. Biol. 199(3): 603-607)Peaceful and timid with other species, but territorial toward its own kind and other mormyrids (Seriously Fish).
Seriously Fish: Gnathonemus petersii · Wikipedia: Peters's elephantnose fish (cites Nilsson 1996, J. Exp. Biol. 199(3): 603-607)Demersal = bottom-living; sifts soft sand for worms at night.
FishBase: Gnathonemus petersii summarySeriously Fish's quick rating shows 'Easy' (5 of 8 measures, with diet, compatibility and hardiness marked unknown), yet the same page says it is very sensitive to poor water and to medications including salt, needs a group of 5+, a large tank and dim light. FishBase says it is not recommended for home aquaria. Sources conflict, so no value set; legacy 'hard' remains a defensible editorial choice.
Seriously Fish: Gnathonemus petersiiLegacy has no native range.
FishBase: Gnathonemus petersii summary · Seriously Fish: Gnathonemus petersiiLegacy states the kinked/straight anal fin rule as fact; Seriously Fish treats it as unconfirmed.
Seriously Fish: Gnathonemus petersiiSeriously Fish suggests tank life may blur the electric signals that tell the sexes apart, which may stop spawning.
Seriously Fish: Gnathonemus petersii · Wikipedia: Peters's elephantnose fish (cites Nilsson 1996, J. Exp. Biol. 199(3): 603-607)The brain figure is from Nilsson 1996 (J. Exp. Biol.), via Wikipedia; the primary paper was not fetched. Seriously Fish also notes it has been used as a water-quality monitor in parts of Germany and the US.
Wikipedia: Peters's elephantnose fish (cites Nilsson 1996, J. Exp. Biol. 199(3): 603-607) · Seriously Fish: Gnathonemus petersii