Serpae tetra

Serpae tetra
Conservation status
Least Concern  (IUCN 3.1) [1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Characiformes
Family:	Acestrorhamphidae
Genus:	Megalamphodus
Species:	M. eques
Binomial name
Megalamphodus eques (Steindachner, 1882)
Natural range in South America
Synonyms [2]
Chirodon eques Steindachner, 1882 Cheirodon eques (Steindachner, 1882) Hyphessobrycon eques (Steindachner, 1882) Tetragonopterus callistus Boulenger, 1900 Hyphessobrycon callistus(Boulenger, 1900) Hemigrammus melasopterus C. H. Eigenmann & Kennedy, 1903 Hyphessobrycon serpae Durbin, 1908

The serpae tetra (Megalamphodus eques), also known as the Callistus tetra, red tetra, jewel tetra or blood characin, is a species of freshwater ray-finned fish belonging to the family Acestrorhamphidae, the American tetras. This species is found in South America.

Taxonomy

The serpae tetrawas first formally described as Chirodon eques in 1882 by the Austrian ichthyologist Franz Steindachner with its type locality given as Villa Bella and Obidos on the Amazon River in Brazil. The genus name should have been spelt Cheirodon . ^[2] In 2024 this species was reclassified in the genus Megalamphodus which had been proposed by Carl H. Eigenmann in 1915 and is the type genus of the subfamily Megalamphodinae, the red tetras, within the American tetra family, Acestrorhamphidae. ^[3] This family is classified within the suborder Characoidei of the order Characiformes. ^[4]

Etymology

The serpae tetra is classified in the genus Megalamphodus, which is Greek and means "with spacious ways", a name coined by Carl H. Eigenmann which he gave no explanation for. It may be an allusion to the “very large” fontanels, the frontal bones being described as “entirely separate”', that is with a space between them and the parietal bones. The specific name, eques means "horseman" or "rider", an allusion Steindachner did not explain but which may refer to the saddle like mark on each side, Steindachner used this name for other fishes with similar markings. ^[5]

Description

The serpae tetra has a maximum standard length of 4 cm (1.6 in), ^[6] the body is laterally compressed and high. The overall colour is reddidh-olive brightening to scarley along the flanks. There is a comma shaped black humeral spot and the dorsal fin is black, ^[7] with the anal and caudal fins being red. ^[8]

Distribution and habitat

The serpae tetra has a disjunct native range, with subpopulations in the Amazon basin of Brazil and in the La Plata basin in Argentina, Brazil, Bolivia, Paraguay and Uruguay. It has also been introduced to French Guiana and eastern Brazil. Its preferred habitat includes slow-flowing tributaries, floodplain lakes and associated flooded environments, it readily colonises anthropogenic aquatic habitats, such as artificial ponds and reservoirs. It is normally found close to submerged aquatic vegetation. ^[1]

Utilisation

The serpae tetra is one of the most popular fishes in the aquarium trade but almost all of the fishes traded are captive bred and few are taken from the wild. ^[1]

See also

• List of freshwater aquarium fish species

References

1. Lima, F. (2023). "Hyphessobrycon eques". IUCN Red List of Threatened Species . 2023 e.T186897A1820024. doi: 10.2305/IUCN.UK.2023-1.RLTS.T186897A1820024.en . Retrieved 26 December 2023.
2. Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Megalamphodus". Catalog of Fishes . California Academy of Sciences . Retrieved 12 October 2025.
3. Melo, Bruno F; Ota, Rafaela P; Benine, Ricardo C; et al. (2024-09-01). "Phylogenomics of Characidae, a hyper-diverse Neotropical freshwater fish lineage, with a phylogenetic classification including four families (Teleostei: Characiformes)" . Zoological Journal of the Linnean Society. 202 (1) zlae101. doi:10.1093/zoolinnean/zlae101. ISSN   0024-4082.
4. R. Fricke; W. N. Eschmeyer; R. Van der Laan (2025). "ESCHMEYER'S CATALOG OF FISHES: CLASSIFICATION". California Academy of Sciences. Retrieved 12 October 2025.
5. Christopher Scharpf (3 October 2025). "Family ACESTRORHAMPHIDAE Eigenmann 1907 (American Tetras)". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf. Retrieved 10 October 2025.
6. Froese, Rainer; Pauly, Daniel (eds.). "Megalamphodus eques". FishBase . April 2025 version.
7. "Serpae Tetra - Hyphessobrycon eques Fish Profile & Care Guide". Aquadiction. Retrieved 13 October 2025.
8. "Serpae Tetra - Hyphessobrycon eques". Fishlore. 14 May 2020. Retrieved 13 October 2020.

• H. Axelrod; G. Axelrod; W. Burgess; N. Pronek; H. Axelrod; J. Walls (2007). Dr. Axelrod's Atlas of Freshwater Aquarium Fishes (Eleventh ed.). T.F.H. Publications. p. 292.