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Family: Characidae, Hemigrammus Clade

Common Names: Serpae Tetra, Red Minor Tetra

Origin and Habitat: South America; found over a wide geographical area of the Amazon, Parana, Guapore and Paraguay River basins.

Compatibility/Temperament: Sometimes peaceful, but known to be aggressive and a fin nipper. Must be kept in a group, minimum 6 but 8+ is more likely to help curb the fish's aggressive (fin-nipping) tendancies. Should never be kept with slow or long-fin fish (guppies, angels, discus, gourami, betta) but only with active species.

Serpae Tetra Diet

They are omnivorous and will appreciate almost every food given to them.


Up to 1.5 inches.

Minimum Tank Suggestion

24-36 inches if a species-only tank; when other fish species are included, a tank of 55 gallons or preferably larger is recommended so a sizeable group can be accomodated in consideration of their behaviour.

Water parameters for Serpae Tetra

Soft to moderately hard (hardness to 25 dGH) acidic to basic (pH to 7.6) water, temperature 22-28C/72-82F. Occurs in sluggish streams and ponds, frequently around marginal vegetation and submerged branches. Although it tolerates harder basic water, it is at its best in colouration and behaviour--and will only spawn--in soft, acidic water.


This species is closely related to some 30 Hyphessobrycon species known as the rosy tetra clade that includes H. bentosi, H. rosaceus, H. megalopterus [Black Phantom], H. sweglesi and H. erythrostigma ["bleeding hearts"] to name but a few. It shares the common traits of a black dorsal fin and a dark (in this species black) humeral or shoulder blotch immediately posterior of the gillcover, and (usually) a red body colouration. The shade of red varies on fish from different geographical regions. The dorsal is edged in white. This species is readily discerned from all the other rosy tetra species by the dark colour pattern on the posterior part of the anal fin that expands from the black distal (furtherest from the body) border of this fin. Weitzman & Palmer (1997) note that this dark pattern is somewhat variable on wild-caught specimens from different locations [see below].

Behaviour can be unpredictable; keeping the species in large groups and in larger tanks tends to lessen its aggressiveness. This variant behaviour, like the anal fin pattern mentioned above, may also partly be due to significant variations between the fish. Dr. Stanley Weitzman (1997) has suggested that the "species" may be a complex of closely related species that are geographically quite variable and occur over a wide area of Amazonia; it is quite possible that this "species" may actually be several different species, each endemic to specific river basins; this will only be ascertained after collections from many locations have been studied in detail.

Many of the fish now available in the hobby are commercially raised and differ from wild-caught fish with respect to the dark shoulder or humeral patch. Commercially bred fish are descended from hybrids (perhaps unintentionally) of fish from different geographical areas, and the patch is shorter or all but absent on most; on wild-caught fish, this patch is black, elongate and slightly triangular.

This is reputed to be one of the easiest characins to breed. As these are egg scatterers, fine leaved plants like myriophyllum, ambulia, cabomba and hornworts should be used along with dark substrate. Water should be soft and acidic with readings at pH of 6.5 and dGH not exceeding 8, and lighting quite dim.

This fish has gone through several name changes, being placed in four different genera before being assigned to Hyphessobrycon by Weitzman & Palmer (1997). Within this genus, the names H. callistus and H. serpae are now recognized as synonyms of H. eques and not valid distinct species; fish still appear in stores under these synonyms.

The genus Hyphessobrycon--the name from the Greek hyphesson [believed to mean "slightly smaller"] and brycon [=to bite]--was erected by C.H. Durbin in 1908 and presently contains more than 100 valid species. The classification is deemed incertae sedis [Latin, "of uncertain placement"]. It was formerly considered within the subfamily Tetragonopterinae, but Javonillo (2010) suggest that this subfamily should be restricted to species within the genus Tetragonopterus since they do not share physiological characteristics with species in other genera such as Hyphessobrycon.

Authors that have recently studied the systematics of the genus Hyphessobrycon have unanimously pointed out that the group is not well defined and its monophyly is yet uncertain. [A monophyletic genus is one wherein the species share a common ancestor, thus linking them together physiologically.] Mirande (2009) for example has proposed several revisions to the family Characidae based upon phylogenetic diagnosis. Some genera have been moved to a new subfamily, while others are now (temporarily) assigned to a specific clade within the family pending further study. The recognition of groups of species [clades] within Hyphessobrycon is based primarily on similarities of color patterns; an hypothesis of its intra-relationships is currently unavailable, except for the rosy tetra clade proposed as monophyletic by Weitzman & Palmer (1997).

Hyphessobrycon has until recently been differentiated from Hemigrammus solely on the basis of the fish in Hemigrammus possessing a scaled caudal fin; this however is now known to be unreliable, since it occurs in intermediate conditions (de Lucina, 2003).


de Lucena, Carlos Alberto Santos (2003), "A new characid fish, Hyphessobrycon scutulatus, from the Rio Teles Pires drainage, upper Rio Tapajos system (Ostariophysi: Characiformes: Characidae)," Neotropical Ichthyology 1 (2), pp. 93-96.

Javonillo, Robert, Luiz R. Malabarba, Stanley H. Weitzman and John R. Burns (2010), "Relationships among major lineages of characid fishes (Teleostei: Ostariophysi: Characiformes), based on molecular sequence data," Molecular Phylogenetics and Evolution, Vol. 54, No. 2 (February 2010).

Mirande, J. Marcos (2009), "Weighted parsimony phylogeny of the family Characidae (Teleostei: Characiformes)," Cladistics, Vol. 25, No. 6 (July 2009).

Weitzman, Stanley H. & Lisa Palmer (1997), "A new species of Hyphessobrycon (Teleostei: Characidae) from the Neblina region of Venezuela and Brazil, with comments on the putative 'rosy tetra clade'," Ichthyological Exploration of Freshwaters volume 7 (no. 3), pp. 209-242.

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