The raphidophytes, formally known as Raphidophycidae[2] or Raphidophyceae (formerly referred to as Chloromonadophyceae and Chloromonadineae),[3] are a small group of eukaryotic algae that includes both marine and freshwater species.

Unlike other heterokontophytes, raphidophytes do not possess the photoreceptive organelle (or eyespot) typical of this group.

In terms of ecology, raphidophytes occur as photosynthetic autotrophs across a range of aquatic systems.

Off the Japanese coast, the resulting red tides often cause disruption to fish farms, although raphidophytes are not usually responsible for toxic blooms.

[6] Others considered them as related to the Chrysophyceae, Dinophyceae, or Cryptophyceae [7] Currently, raphidophytes are regarded as an independent lineage of algae within the class Raphidomonadea, which also includes the heliozoan group Actinophryida.