Black Phantom Tetra (Megalamphodus megalopterus)

Aquarists don’t often take the time to think about what a species’ scientific name actually means, but, for the Black Phantom Tetra, this can be informative. It belongs to Megalamphodus, a hugely diverse and poorly understood genus in South America. And its species name is megalopterus, which translates roughly as “large fin”, alluding to the spectacular dorsal fin of males, which becomes greatly exaggerated in size and darkens to a stately black.

The species is native to certain river basins in the western portion of the Amazon, which together form part of the vast Pantanal—the world’s largest tropical wetland. Here, in the crystal clear waters and lush, emergent vegetation, the Black Phantom Tetra abounds in large schools. However, aquarium specimens are now typically available from individuals that have been bred in commercial fish farms for generations.

Caring for this species is no different than most other tetras from the tropical Amazonian river basin. Warm temperatures and neutral or acidic conditions are ideal, but, having been bred for so long in captivity, the species is fairly undemanding and quite hearty. It is exceptionally peaceful and is best mixed with tankmates which will pose it no threat, either from predation or by nipping on its elaborate fins.

Males and females are noticeably different in appearance, Aside from the deeper, fatter body of females, they also differ in having smaller fins which tend to be red, rather than black, in coloration. Males use their elaborate finnage in display with one another, fighting for the right to breed with nearby females. This is easily recreated in the confines of a fish tank, provided that several males and several females are kept together. The species will breed regularly if well-cared for, scattering their eggs loosely along the bottom, and, in a densely planted aquarium where the fry can safely hide, it becomes possible for a few to even reach adulthood without any real effort.