Fishes of the danio clade tend to have horizontal stripes, rows of spots, or vertical bars, and often have long barbels.

Species within the devario clade tend to have vertical or horizontal bars, and short, rudimentary barbels, if present at all.

Two fossil danionins, tentatively assigned to Rasbora ('Rasbora' antiqua and 'Rasbora' mohri) are known from the Eocene of Sumatra, Indonesia, representing the earliest record of the group.

They are generally active swimmers, occupying the top half of a tank and eat just about any type of aquarium food.

They occur in stagnant water with pH values between 3 and 5 caused by peat, which accumulates from a dense canopy.

The sole species within Myers' Daniops, D. myersi, has long ago been found to be a synonym of Devario laoensis, but his genus Brachydanio lasted for much longer, as it included most of the fish now classed as Danio, whereas Danio included most of the fish now classed as Devario.

In 1941, H.M. Smith attempted to unite all the Brachydanios and Danios species into one genus on the basis of a fish from Thailand, which was supposed to bridge the gap.

The genus is identified as a danionin due specializations of its lower jaw and its numerous anal fin rays.

Also, rasborins have the generalized cyprinid principal caudal fin ray count of 10/9, while all Asian cyprinids with fewer than 10/9 principal caudal fin rays are all diminutive species of Danioninae, including Celestichthys, M. erythromicron, Danionella, and Paedocypris.

[6] In 2007, an analysis of the phylogenetic relationships of the recently described genus Paedocypris was published, placing it as the sister taxon to Sundadanio.

There is still uncertainty over the exact relationships for the three miniature taxa: Danionella, Paedocypris, and Sundadanio as all three have shown variability in phylogenetic position among different studies, both molecular and morphological.

Tanichthys is often regarded as a danionin by aquarists and grouped as such in some older aquatic publications, but no scientific basis exists for this, a fact stated on numerous occasions by Brittan and others.

[4] A number of the species have only been recently discovered, in remote inland areas of Laos and Myanmar, and do not yet have scientific names.