When in doubt, follow your nose-- just like the elephantnose fish! This fish's 'nose', which is really an extension of the mouth, is covered in sensitive organs called schnauzenorgan. To navigate and find prey, the elephantnose fish emits weak electrical pulses from its tail; when they hit an object, the pulses bounce back to be detected by the schnauzenorgan, similar to echolocation!
(Image: An Ubangi elephantnose fish (Gnathonemus petersii) by Timo Moritz)
Anatomy: elongated body; toothed or bony tongues; long or absent dorsal and anal fins positioned near the caudal fin; large swim bladder enables them to breathe at the surface of the water; most are adapted for surface feeding
Diet: arthropods, fish, snails, frogs, lizards, snakes, mice, bats, and small birds
Habitat/Range: slightly acidic freshwater in South America, Africa, Australia, and Southern Asia
Evolved in: Late Jurassic
(source)
Do you have a favorite in Osteoglossiformes?
One or more of my favorite animals is in Osteoglossiformes
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 25, 2025
Propaganda under the cut:
Freshwater Butterflyfish (Pantodon buchholzi) (image 4) have very large pectoral fins. If enough speed is built up underwater, a butterflyfish can jump and glide a small distance above the surface to escape predators. It wiggles its pectoral fins as it glides, with the help of specialized, enlarged pectoral muscles.
Arowanas (genus Osteoglossum) can jump up to 2 m (6.6 ft) out of the water to pick their prey off of branches, tree trunks or foliage, which has earned them the local name "water monkeys". They are the largest fish in the world to catch most of their food out of water.
Male arowanas brood their young within their mouth, only fully releasing them when they are about 7 cm (2.8 in) long.
The endangered Asian Arowana (Scleropages formosus) (image 1) is also known as the “dragonfish”, due to its large metallic scales and long barbels giving it a resemblance to the Chinese dragon. The popularity of this beautiful, auspicious fish has had both positive and negative effects on their status as endangered species, as they are in high demand in the home aquarium trade. Legal pet Asian Arowanas must be bred in captivity on a fish farm for at least two generations, have a certificate of authenticity and a birth certificate, and an implanted microchip to identify the individual. There are over 150 CITES-registered Asian Arowana farms in Singapore, Malaysia, Indonesia, and other Southeast Asia countries, producing Asian Arowana for commercial purposes. But the actual number of Asian Arowana farms in the world could be much higher than that, probably over 350, the majority of them unregistered.
The Arapaima (Arapaima gigas) (see gif above) is the largest truly freshwater fish, commonly measuring 200 cm (6.6 ft) with records of up to 450 cm (15 ft). Adults may weigh up to 200 kg (440 lb).
Arapaima parents have been observed using their mouths to dig holes in the substrate to create a nest for their eggs. The males will remain by the nest to protect their offspring for three to six months.
Arapaima are becoming increasingly rare in their native habitat of the Amazon and Tocantins-Araguaia river basins, but are invasive in Bolivia and Indonesia after purposeful and accidental releases.
A 13-million-year-old fossil of an Arapaima (or very similar species) has been found in Colombia, in the Villavieja Formation, which dates from the Miocene epoch.
The African Arowana (Heterotis niloticus) (actually a relative of arapaimas rather than arowanas) is the only Osteoglossiform to feed extensively on plankton.
Native to freshwater habitats in Cambodia, China, Hong Kong, Laos, Macau, Thailand, and Vietnam, the Clown Featherback (Chitala ornata) (image 2) is considered one of the world’s most invasive species, as it often outgrows home aquariums and is then released into the “wild” outside its native range.
The Giant Featherback (Chitala lopis) was declared to be extinct in 2020, but a small surviving population was rediscovered on Java, Indonesia in 2023.
The African Knifefish (Gymnarchus niloticus) and freshwater elephantfishes (family Mormyridae) (image 3) are able to produce a steady but weak electric field, used for finding their prey, usually small invertebrates buried in muddy substrates.
The African Knifefish can swim equally well forwards or backwards, relying on its electric senses to “see” behind it.
Freshwater elephantfish are known to have a large brain size and unusually high intelligence.
The Medjed (likely a fish in the genus Mormyrus) was a kind of elephantfish sacred in the city Oxyrhynchus, in ancient Egyptian religion, as the fish that ate the penis of Osiris. Archaeologists have found fishes depicted as bronze figurines, mural paintings, or wooden coffins in the shape of fishes with downturned snouts, with horned sun-disc crowns like those of the goddess Hathor.
I've done Arapaima gigas, but not Arapaima in general! Good choices!
Have you seen an arapaima (Genus: Arapaima)?
I have now
Yes, in photos/videos
Yes, irl
I'm not sure
Voting ended onNov 15, 2025
Both of these photos are thanks to the Smithsonian National Zoo & Conservation Biology Institute. I believe they are both of Arapaima gigas sadly, but at least they're gorgeous photos.
