Order Characiformes
Family Characidae (American Tetras)
Subfamily Stevardinae
Genus Pseudocorynopoma.
— Dragonfin Tetra — Pseudocorynopoma doriae [Perugia, 1891]. Synonyms: Bergia altipinnis, Chalcinopelecus argentinus. Brazil, Argentina, Paraguay, Uruguay. 7 cm. Coloration is silvery-gray with a bluish line. Tail base with a dark spot and black-and-white dots at the tips of the lobes. The male differs from the female in having larger dorsal and anal fins, the first rays of which elongate in aging specimens.
Peaceful, active, schooling, jumpy fish capable of short leaps. Requires elongated aquariums with sufficient swimming space and light vegetation. Cover the aquarium, as they are excellent jumpers. Suitable for keeping with similarly fast and active schooling fish. Mostly stays in the middle and upper water layers. Courtship behavior is particularly interesting: the male circles around the female for several hours with his head lowered. pH 6-7.5; dH up to 16°; T 20-24°C.
Genus Pterobrycon.
— Semaphore Tetra — Pterobrycon myrnae [Bussing, 1974]. Synonym: Pristis myrnae. Costa Rica. 5-7 cm. The male is slimmer, with a black rhomboid scale on its head, and a coppery sheen to its coloration. The female is silver-colored. Very delicate, jumpy fish. Highly active, cheerful fish, staying in the upper and middle water layers. Keep only in a large school. Prefers clean, transparent water, plenty of light and aeration. Well suited for community aquariums with light vegetation, hiding spots, and plenty of swimming space. Internal fertilization.
Genus Tyttocharax.
— False Blue Tetra — Tyttocharax cochui [Ladiges, 1950]. Synonyms: Microbrycon cochui, Tyttocharax boehlkei. Peru, Amazon River basin. 2.5 cm. Transparent body with a high back and a large, deeply cleft caudal fin. Body features a sky-blue metallic sheen. Depending on the light, the flanks shimmer with copper or bluish hues. Dorsal fin is black with a reddish margin.
In both sexes, the upper lobe of the caudal fin is pink and red, while the lower is whitish. Males have a broad yellow zone with a black margin on the caudal fin. Their fins have a beautiful sheen depending on the lighting. Males are not only larger but also more colorful. Keep only in a large school in a species tank or with shrimp. Swims in the upper third of the aquarium. Water should be soft and clean. T 22-26°C.
— Tyttocharax tambopatensis [Weitzman & Ortega, 1995]. Peru, Tambopata and Manu River basins. 1.7 cm. Translucent body in blue tones, darker at the body edges, gill covers, and tips of the caudal fin. The lateral line usually has a golden tint smoothly transitioning to turquoise-blue. Fins are generally transparent, except for the caudal fin. Males are slightly larger than females, with more intense blue coloration.
This is a very small, active, schooling fish. Aquarium with stem plants and floating plants, moderate lighting. Fish are very sensitive to sudden water parameter changes; it is recommended to introduce them to an established aquarium with low nitrate and phosphate levels, as these fish are susceptible to them. Soft water with dH below 6° is required. Peat filtration is highly desirable. Any fine aquarium food. pH 4.5-7.5; T 23-28°C.
Mimagoniates barberi, inequalis, lateralis, microlepis.
Acrobrycon ipanquianus, Corynopoma riisei, Knodus borki, Knodus meridae. 
