Taxonomy & naming
Glossamia aprion was described by Richardson in 1842 from the King's River near Port Essington, Northern Territory, Australia. It sits in Apogonidae, the cardinalfishes, one of the few freshwater lineages in a mostly marine family. The common name mouth almighty comes from its very large mouth.
Morphology
FishBase gives a maximum length of 7 in SL. The body is deep-bellied and the mouth is wide and oblique, built for engulfing prey whole.
Habitat
FishBase lists it as a freshwater, benthopelagic fish of tropical water, found in New Guinea and Australia. It gives a temperature range of 23 to 25 C, a pH of 7.0 to 7.5 and a hardness of 12 to 20 dH.
Feeding
FishBase records no diet for the species. Cardinalfishes are predators, and the mouth shape points to fish and large invertebrates taken by ambush, mostly at night.
Mating
FishBase notes distinct pairing during courtship and spawning.
Breeding
The male is the mouthbrooder. He holds the fertilised eggs in his mouth until they hatch. FishBase gives no clutch size or incubation time.
In the aquarium
The species appears in the trade as a predatory oddball. Keep it in a large tank with robust tankmates it cannot swallow; anything smaller than about half its length is food. Offer meaty foods, and expect it to hide by day and feed at night. FishBase's range of 23 to 25 C, pH 7.0 to 7.5 and 12 to 20 dH is the reference for water.
Conservation
The IUCN Red List lists Glossamia aprion as Least Concern, assessed 15 February 2019.