During the late 20th century, advancements in molecular and ultrastructural studies allowed the transfer of many of these groups out of Ochromonadales, and the order was reduced to a single family Ochromonadaceae.

[10] Ochromonadales is an order of golden algae (class Chrysophyceae), a group of photosynthetic heterokonts (phylum Ochrophyta).

[8] It initially contained numerous families united only by being primarily monadoid (flagellate), palmelloid or amoeboid throughout their life cycle.

[13] In 1968, Bourrelly again modified the composition of the order, placing within it all monadoid, coccoid or filamentous golden algae that generate cells with two flagella in at least one stage of their life cycle.

He implemented three suborders:[14] In the following decades, most of these families were transferred to other orders and classes with the advent of ultrastructural studies and molecular phylogenetics.

Jahn Throndsen proposed in 1993 classifying five families within Ochromonadales: Ochromonadaecae, Chrysococcaceae, Chromulinaceae, Dinobryaceae and Paraphysomonadaceae.

[21][22] This family, first described by German botanist Ernst Lemmermann in 1899, contains genera of free-floating, naked single-celled organisms with two flagella.