Slender Danios

About

Slender Danios (Brachydanio sp. hikari) are a probably undescribed species that first showed up in the hobby around 2002, initially sold under two different names because males and females look different enough that dealers thought they were separate fish. DNA work eventually confirmed they are one species, genetically distinct from the closely related B. kerri, though the question of whether this is truly its own species or a particularly colorful form of kerri remains open. The most reliable way to tell them apart is the central body stripe, which extends into the caudal fin in this species but stops at the caudal peduncle in kerri. They originate from the Tanintharyi River drainage in southern Myanmar, part of the Tenasserim River system. In the aquarium they are thoroughly easygoing, placing no real demands on water chemistry and mixing well with other small community fish including tetras, livebearers, rainbowfish, and loaches. As a schooling species they genuinely need to be kept in groups of eight or more, not just for their own comfort but because males color up noticeably when they have rivals around. This is an accessible fish for newer keepers who want active, open-water swimmers in a well-planted community setup.