It seems to be closely related to A. diaphanus due to some derived characters of the internal anatomy, but a conclusive assessment of its relationships has not been prevented by its paedomorphic features and scarcity of study material.

[1] A. pulex can be distinguished from A. diaphanus by a number of characteristics, including the presence of a faint pattern of eight bands formed by internal chromatophores and the lack of teeth.

[1] A. diaphanus inhabits shallow, narrow, clear water, moderately swift-flowing stream and is found buried in the sand.

Apparently fossorial by daylight, it is found buried in coarse clear sand at the stream edge, in areas shaded by dense tropical rainforest.

[1] A. pulex is thought to feed on microscopic fauna like protozoa, rotifers, and nematodes since it inhabits interstitial spaces among sand grains in nutrient-poor, clear-water and backwater streams.