斯氏多齿脂鲤 · Red Phantom Tetra

Overview

Megalamphodus sweglesi, the red phantom tetra, is a small schooling fish whose extended male fins and display colors are best appreciated in a planted aquarium with a proper group. The intensely red form sold in the trade belongs to the same species.

Distribution & habitat

Its native range spans the upper and middle Orinoco drainage in Colombia and Venezuela. Smaller tributaries, oxbows, and seasonally flooded forests appear to be favored over the main river. Habitat varies: palm-associated streams in the Llanos can be clear, sandy, and densely vegetated, while other populations occupy flowing blackwater or quieter floodplain lakes. Seasonal flooding reshapes these environments extensively.

Aquarium setup

Allow a footprint of about 80 × 30 cm or more. A planted layout or sand with driftwood and branches can provide cover while leaving room for the group to move. Leaf litter adds shelter and supports microorganisms that adults and fry can eat as it decomposes.

Diet & feeding

The wild diet probably includes small invertebrates, algae, and fallen fruit. In captivity, alternate suitably sized prepared foods with live or frozen Daphnia, Artemia, and bloodworms. Offer portions and particle sizes that the fish can handle readily.

Behaviour & compatibility

This is generally a peaceful companion for similarly sized, mild-mannered fishes. Keep at least 8–10 individuals, including both sexes. Males establish temporary rankings and display to attract females; a substantial group provides scope for these interactions.

Sexual dimorphism

Male dorsal and anal fins become extended. Mature females have deeper bodies and fuller abdomens.

Breeding

Eggs are scattered and receive no parental protection. For a deliberate breeding attempt, use a dim aquarium with mature water and fine plants, spawning mops, mesh, or marbles that put the eggs beyond the adults' reach. Slightly acidic to neutral water, a temperature toward the upper end of the suitable range, and gentle aeration are appropriate.

Condition the fish well, then introduce a pair or one or two males with several females. Spawning often follows the next morning. Remove adults once eggs are found. Newly feeding fry need Paramecium or a very fine fry food before they can manage Artemia nauplii or microworms.

Notes

The red commercial form, formerly called “rubra,” does not owe its color solely to its food. Morphological work published in 2014 treated it as conspecific with the ordinary form. A proposed association between red coloration and blackwater habitat remains a hypothesis rather than a reliable way to establish a fish's origin.