Teratichthys antiquitatis was a carangid, or jack relative, from the London Clay and one of the historically named teleosts from the formation. Carangids are typically active marine swimmers, many feeding on smaller fishes and crustaceans. A similar predatory or opportunistic role is plausible for Teratichthys, although the details of its diet are inferred from family-level ecology rather than direct evidence.

The species is represented by cranial and skeletal remains rather than otoliths alone. Its compact carangid head and associated bones document the early presence of jack-like fishes in the Ypresian sea and add to the diversity of active mid-water teleosts in the assemblage.