Emperor Tetra

Geographic Origin and Biotope: Western Colombia (San Juan and Atrato river basin). Shares the same habitat as the Amphiloxus: slow secondary jungle streams.

Taxonomy and Morphology: Emperor Tetra (Nematobrycon palmeri). Solidly built Tetra, almost horizontal dorsal profile and curved belly (profile of an inverted knife). No dorsal adipose fin.

Social Behavior: In juvenile age it forms schools; as adults, males develop marked territoriality. They position themselves 20-30 cm (8-12 inches) from each other to show off their fins, dancing upside down as a threat.

Coloration and Sexual Dimorphism: Royal Livery: dark central line edged with cream and an iridescent lavender/light blue back. The male is a masterpiece: bright neon blue eyes and the central spine of the tail elongates into a very elegant "skewer" (Caudal trident). The female has green-yellow eyes and a rounded tail.

Aquarium Setup: 80 cm (32 inches) tank. Shade is fundamental: woods loaded with Epiphytes (Bolbitis, Microsorum), floating lenses (Limnobium) and dark substrate. A Palmeri under intense white LED lights will fade becoming invisible.

Diet and Feeding: Totally undemanding, but being a characin, requires high protein levels. Administer freeze-dried bloodworms, live Brine Shrimp (which it hunts fiercely) and sinking flakes/granules (does not eat on the surface).

Water Quality: Rustic. Among the easiest Tetras to manage regarding chemistry. Excellent at neutral pH (7.0) and comfortably accepts treated tap water.

Compatibility and Tankmates: Males ignore each other (if there is space) but can persecute very slow fish (male Guppies) mistaking them for territorial rivals. Excellent with Apistogramma and large characins.

Aquarium Reproduction: Quite accessible. They spawn early in the morning in roots or moss. If the parents are well fed, a few fry will manage to escape them and grow undisturbed in the crevices of the mother tank.

Risks and Diseases: Tuberculosis from overcrowding. If crammed (e.g. 20 specimens in 60 cm / 24 inches), territorial stress will cause immunodeficiency, leading them to die one by one from Mycobacterium (progressive wasting).