Phenacogaster megalostictus is a slender, mid-water characin native to the Amazon basin, characterised by its prominent black midlateral stripe and a distinctive large dark spot — the 'megalostictus' or large spot — located behind the gill cover or on the flank. Growing to only about 8 cm, it is a peaceful schooling species well suited to soft-water planted or biotope aquariums alongside other small to medium Amazonian fish.
In the aquarium this species requires soft, slightly acidic water — pH 5.5–7.5 — warm temperatures, and good plant cover or driftwood for security. It is an undemanding fish in terms of feeding and will accept a wide range of prepared, frozen, and live small foods. In groups of eight or more it displays confident schooling behaviour that rewards patient observation.
Phenacogaster megalostictus is not commonly seen in the trade but is occasionally available from specialist importers. It is an attractive, elegant species that occupies the same niche as many commonly kept tetras but with a distinctive pattern that sets it apart. It is suitable for intermediate hobbyists and fits well into a diverse South American community aquarium.