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.

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

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.