Allopseudaxinoides is a genus which belongs to the phylum Platyhelminthes and class Monogenea; all its species are parasites of fish.

[1] Species of Allopseudaxinoides are ectoparasites that affect their host by attaching themselves as larvae on the gills of the fish and grow into adult stage.

This larval stage is called oncomiracidium, and is characterized as free swimming and ciliated.

In fact, species of Allopseudaxine have a large body tapering anteriorly, and a unilateral, oblique haptor, (which means that they have a single oblique row of clamps,) giving them a triangular appearance.

However, species of Allopseudaxinoides can be distinguished from Allopseudaxine by a complete absence of vaginae or the presence of rudimentary ones,[2] the presence of thickenings of clamps capsule,[1] and an accessory clamp sclerite.