Cryptomyrus is a genus of weakly electric elephantfish in the family Mormyridae, part of the bonytongue order Osteoglossiformes. It was described from Gabon's Ogooue River system, and both species the atlas covers, Cryptomyrus ogoouensis and Cryptomyrus ona, are known only from that West-Central African drainage. Like other mormyrids, Cryptomyrus generates a weak electric field from a caudal electric organ and reads distortions in that field with electroreceptors covering the skin, using the system to navigate and probe the riverbed for food in dark or turbid water at night. The genus name nods to how unremarkable its external anatomy looks next to showier mormyrid relatives, many of which carry an elongated chin barbel or a dramatically shaped snout that Cryptomyrus mostly lacks.
At roughly 4.5 in adult length, Cryptomyrus is a small mormyrid, and given how recently it was recognized as a distinct genus, it is essentially unknown in the aquarium trade; the atlas's coverage here reflects taxonomic and biogeographic interest rather than any hobby following. Elephantfishes as a group are notoriously demanding aquarium subjects regardless of species, sensitive to water quality, easily stressed in bright or crowded tanks, and dependent on live or frozen invertebrate foods, so anyone who does encounter Cryptomyrus should assume it needs the same soft, dim, well-oxygenated setup that keeps other mormyrids alive. Neither species has yet been formally assessed for the IUCN Red List, which is typical for narrow-range fish described within the last decade.