It is one of the most abundant foraminifer genera worldwide and is found in sheltered, shallow marine intertidal environments, sometimes in brackish waters.

[2] The classification of the genus Ammonia in species is controversial.

While several different forms exist, many authors consider the genus to consist of a single species, Ammonia beccarii, with many ecophenotypes.

However, recent molecular studies revealed that the genus consists of many species, although they may be difficult to discriminate based on morphology.

[3] Based on a comparison between molecular results and morphology, the following species appear to be valid: Additionally, several other molecular types have been discovered that do not match any of the described species and thus possibly represent new taxa.