Rosy Tetra

About the Rosy Tetra

Species Type: Freshwater Fish
Category: Characins

Care Level: Easy. Does well in a slightly more narrow range of water parameters and shouldn't be used to cycle an aquarium. Will eat most prepared foods. May have some specific care requirements in terms of particular water parameters, social behaviors, food items etc.

Origin: South America: Guyana and Suriname, in sluggish forest streams. Reports in earlier literature [by Eigenmann, Gery, Sterba, Baensch & Riehl] of this fish occurring in the Rio Guapore and Mato Grosso area in southern Brazil are probably incorrect (Weitzman & Palmer, 1997).

Compatibility/Temperament: Very peaceful and recommended for a community aquarium of similar fishes including characins, small catfish and loaches, gourami, angelfish, dwarf cichlids. This fish must be kept in groups, minimum 6 but preferably more, and remains in the lower half of the aquarium. It readily mixes in with the other related species in the "rosy" or "bentosi" group of Hyphessobrycon, forming groups that may include any of the species.

Description

The Rosy Tetra is one of some 30 species commonly referred to as the "rosy tetra clade" within the genus Hyphessobrycon that share several traits in colour and pattern. All species are somewhat disk-shaped and share the "flag" signal, being a very conspicuous black spot on the dorsal fin, usually underlined by a white or sometimes yellow zone and tipped with white depending upon species. They also share a darkened humeral or shoulder patch immediately posterior of the gill covers. Durbin (1909) in first describing the subject species stated that the humeral (shoulder) patch was absent, but in fact it is present though quite pale in this species; Weitzman and Palmer (1996) state that over a light coloured substrate, the colours pale and the humeral patch is basically non-existent, but over a dark substrate the body colouration deepens and the humeral spot is visible.

These above-mentioned traits are particularly similar between Hyphessobrycon rosaceus and H. bentosi, such that the two fish are frequently confused. The body red of H. rosaceus is somewhat paler than that of H. bentosi, and there are a number of small differing traits respecting the fins. In particular, this species possess white tips on the black pelvic and sickle-shaped anal fins, whereas the fins are pure black on H. bentosi. Previously, the subject species was frequently seen as Hyphessobrycon bentosi rosaceus [as in Baensch & Riehl, Aquarium Atlas I] but the species is now considered to be distinct as H. rosaceus.

Sex differentiation is easy with this species. Males have an elongated dorsal fin that is basically black though occasionally hints of a white top edge appear; females have a small dorsal that is white tipped, with white tips on the ventral and anal fins, and are rounder in the body. Keeping an even ratio of males and females will provide for continual displays by the males with fully extended dorsals, much like the closely-related Black Phantom Tetra and Roberts Tetra. Spawning will occur with subdued light, very soft (< 3 dGH) and acidic (pH below 6.0) water.

In aquaria containing two or more species in the rosy tetra clade, the various species regularly intermingle, and some authors have noted that they may cross-breed. All of them remain in the lower half of the aquarium, interacting socially among plants and wood.

The genus Hyphessobrycon was previously considered within the Sub-Family Tetragonopterinae, but this classification has for some time been deemed incertae sedis [Latin for "of uncertain placement"]. In a study published in 2010, it was determined that the Sub-Family Tetragonopterinae should only be used for species within the genus Tetragonopterus. [Robert Javonillo, Luiz R. Malabarba, Stanley H. Weitzman and John R. Burns, "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)]. Also, J. Marcos Mirande proposed several revisions to the Family Characidae based upon phylogenetic diagnosis in "Weighted parsimony phylogeny of the family Characidae (Teleostei: Characiformes)," Cladistics, Vol. 25, No. 6 (July 2009). Some genera have been moved to a new Sub-Family, while others are now (temporarily) assinged to a specific clade within the Family pending further study.

Rosy Tetra Diet

Primarily carnivorous, will readily accept most prepared foods including flake and frozen.

Size

Maximum size 1.5 inches.

Minimum Tank Suggestion

24-30 inches in length

Ideal water parameters for Rosy Tetra

Soft (hardness to 12 dGH) and acidic to slightly basic (pH to 7.5) water, temperature 24-28C/75-82F. In basic and harder water the colours tend to pale.