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Related FAQs: Characoids/Tetras & Relatives, Characoid Identification, Characoid Behavior, Characoid Compatibility, Characoid Selection, Characoid Systems, Characoid Feeding, Characoid Disease, Characoid Disease 2, Characoid Disease 3, & Characoid Reproduction,

Articles on Characiform families, subfamilies...: The Larger Pencilfishes, Family Anostomidae, Characid/Tetra Fishes, Alestiine Characid Fishes, Characinine/Tetra FishesPiranhas and Relatives, subfamily Serrasalminae, Tetragonopterine/Tetra Fishes, Cardinal Tetras, Distichodus and More, Family Citharinidae, Pike-Characoids, Family Ctenoluciidae, Curimatidae, Trahiras, Family Erythrinidae, Hatchetfishes, Family GasteropelecidaeHemiodus "Sharks" and More, Family HemiodontidaeThe Pike-Like Hepsetid, Family HepsetidaeSmaller Pencilfishes, Splashing Tetras & More, Family Lebiasinidae, Prochilodus/ontids

Survey Articles on: Extreme Characins Part 1: Hatchets, pikes, and other lethal weapons by Neale Monks, Extreme Characins Part 2: Wolves, vampires, and other horrors by Neale Monks & Freshwater Fishes

Characoids/Tetras & Relatives

Bob Fenner  


The Order Characiformes is characterized by "almost always" characteristics: Most have well-developed teeth, and adipose fin is usually present, their bodies are almost always scaled, most have ctenoid ("Comb-like", interdigitating) scales, their anal fins are short to moderately long, their upper jaws are usually not protractile, most have pharyngeal teeth, they almost always lack barbels...


    The bulk of Characiforms are small (don't tell this to a Pacu owner), many are colorful and popular aquarium fishes. They (and other fish groups) are ostariophysians (SuperOrder Ostariophysii... a group of fish families that all possess Weberian apparatus, a series of small bones connecting the gas bladder and middle ear... acting as an amplifier; goblet non-secretory cells... other features) with catfishes, Cypriniiforms (minnows et al.)... Their diversity as a group is astounding... some reproduce outside the water, a few live on the scales of other fishes (lepidophagous), others are fin feeders...


    Their taxonomy is a confusing mess. We will stick with Nelson here (3d ed. currently), but other folks raise and lower different taxa to different rankings, add other groups from elsewhere, subtract some that we have here to relocate elsewhere... Depending on who you believe, there are just one to sixteen separate Characiform families. For us here, we'll show, umm, ten families of about 237 genera and 1,343 species...


Geographic Range:


    Most characiform fishes are found in South America, with a scattering in Central America and handful in the U.S.... about 208 species are found in Africa as well. 


    From full size Pacus at more than two feet long and 25 kilograms to quarter inch jewels, most of the characiform fishes are on the small side; a few inches in length. 


Survey/Links to Families/Subfamilies of Characiform Fishes:


Family Anostomidae: Includes the larger Pencilfish species.

Family Citharinidae: Includes Distichodus; African. Characterized by internal characteristics and dentition. Twenty genera, about 100 species. Two subfamilies (Distchodontinae, Citharinae), but almost all the pet-fish trade sees in the West are a few members of the genus Distichodus.


Family Characidae:


Characins/Tetras . Including Chalceus

Piranhas, Silver Dollars, Pacus, subfamily Serrsaliminae. Toothy Tetras that are big (and medium) on eating flesh to plants...

SubFamily Tetragonopterine:

Small characin fishes of southern U.S. and South America. Example genera: Astyanax, Byconamericus, Bryconops, Cheirodon, Gymnocorymbus, Hemibrycon, Hemigrammus, Hyphessobrycon, Inpaichthys, Megalamphodus, Moenkhausia, Oligosarcus, Paracheirodon, Rachoviscus, Tetragonopterus, Tyttobrycon. 

Egads and little fishes!

Family Ctenoluciidae: Pike Characids

Family Cynodontidae: Dogtooth Characins; tropical S. America. Four described species. Here is Hydrolycus scomberoides at the Steinhart Aq. 2015











Excerpted from: Forgotten Fish; Old-timers with plenty to offer by Neale Monks   

Overlooked tetras 

A handful of tetra species dominate the hobby, things like neons, cardinals, and black widow tetras being available in practically every aquarium store and pet shop. But there are literally hundreds of tetras, and over the years many of them have been kept as aquarium fish. Quite a few of the species that became established early on in the hobby were fairly large and silvery rather than brightly colored. While unquestionably attractive, they were gradually supplanted by the smaller, more colorful species. 

One such fish is the silver tetra, Ctenobrycon spilurus. This species gets to about 3" in length and has a rhomboid shape, and its overall color is silvery-grey. Hardy, omnivorous, and easy to breed, the silver tetra is perhaps a bit too large for the average community tank and certainly far too active to mix with gentle species of fish, but these flaws become virtues when kept in a large tank with robust animals like cichlids, barbs, and catfish that might otherwise scare (or eat) smaller tetras. Like a lot of the fishes covered in this article, the silver tetra is an adaptable fish, and can even be kept in very hard, basic water without problems, something that cannot be said for many of the more delicate tetras. Very similar in terms of hardiness, but more brightly colored, is another silver tetra, Tetragonopterus argenteus. This fish has an almost circular body, a brilliant silver sheen, and bright red ventral fins. A black spot on the base of the tail matches its large black eye. Typically getting to about 3" in aquaria but a little more the wild, this omnivorous species is easy to keep and makes an excellent alternative to the larger (and less plant friendly) silver dollars. 

It isn't just big fish on the list of overlooked tetras; there are some lovely little species too. The x-ray tetra, Pristella maxillaris, is one of the nicest. Basically transparent except for a blood-red tail and brilliant white, black, and yellow markings on its dorsal and anal fins, at about an inch-and-a-half this vivacious, schooling tetra is a durable species that will grace any community tank. Exceptionally adaptable, the x-ray tetra makes an excellent choice for the aquarist stuck with water that is too hard and basic for other tetras to do well; in the wild, this fish is even found in slightly brackish water! Another lovely tetra is the rosy tetra, Hyphessobrycon rosaceus. Salmon-pink in color and barely 1.5" in length, its deep body and remarkably long red and black fins give this fish much more presence than you might imagine. They aren't compulsive schoolers like the x-ray tetras, and instead sort of hang out in groups displaying to one another, making them uncommonly entertaining fish. Perhaps their biggest drawback is their lack of color when crowded into a brightly lit aquarium at a tropical fish store; get them home to a nicely planted aquarium and feed them a mixed diet with a little color-enhancing flake thrown in and you'll soon get to see the fish at their best! While hardy and adaptable, rosy tetras do prefer slightly acidic water, preferably filtered through peat or with blackwater extract added.


Bibliography/Further Reading:


Gery, Jacques. 1977. Characoids of the World. T.F.H. Publications NJ. 672pp.


Nelson, Joseph S. 1994. Fishes of the World.  3d ed. John Wiley & Sons, NY. 600pp.



Castro, Al. 1998. Some are not nice (in answering a hobbyist's queries re the genus Distichodus). AFM 9/98.


Lewis, Peter. 1996. The Distichodids; Experiences with a tribe of the characin family. AFM 3/96.


Walker, Braz. 1969. The distant Distichodus. The Aquarium 10/69.


Piranhas, Silver Dollars, Pacus

Brandy, George and Douglas Campbell. 1984. Some notes on spawning and rearing the Red-Bellied Piranha. FAMA 7/84.


Dunker, Toni. 1960. Catoprion mento, the Wimple Piranha. TFH 1/60.


Jennings, Ron. 1978. How to live with the Red Piranha. FAMA 6/78.


Meegaskumbura, Madhava P.B. 1999. Breeding and caring for Silver Dollars. TFH 9/99. 


Neal, Tom. The Pacu- A friendly giant. TFH 8/98.


Nico, Leo G. and Donald C. Taphorn. 1986. Those bitin' fish from South America. TFH 2/86.


Quinn, John R. 1992. Piranhas. Fact and Fiction. T.F.H. Publications, NJ. 128pp.


Schleser, David M. 1999. Piranhas. A bum rap. Finding the truth about the misconceptions. AFM 3/99.


Schultz, Harald. 1960. Piranhas- Fact and fiction. TFH 9/60.


Vorderwinkler, William. 1960. The Piranha- a menace? TFH 2/60.


Walker, Braz. 1970. The colossal creampuff. The Aquarium 1&7/70.

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