Taxonomy & naming
Awaous flavus was described by Valenciennes in Cuvier & Valenciennes (1837) as Gobius flavus, with the type locality given as Suriname; it is listed as valid by the Catalog of Fishes. Awaous in the New World has been confused with related river gobies, so older records may be mixed.
Morphology
Awaous are elongate, large-headed gobies with fused pelvic fins forming a sucker disc, and they are bigger than most aquarium gobies. FishBase gives a maximum of 3 in SL for this species.
Habitat
FishBase reports the species from estuaries and river deltas over sand and mud, in fresh and brackish water. Its range runs from the Rio Atrato in Colombia to Belem, near the mouth of the Amazon, across Atlantic slope drainages. Large numbers have been collected in shallow flowing water during reproduction. FishBase gives 25 to 27 C, pH 6.0 to 8.0 and 9 to 19 dH.
Feeding
FishBase says it feeds by filtering the substrate or by selectively catching prey, in keeping with the sand-sifting habit of Awaous gobies generally.
Mating
Mating has not been described for this species beyond the observation that adults gather in shallow flowing water to reproduce.
Breeding
Large aggregations in shallow flowing water during reproduction are recorded. Some Awaous are amphidromous, with larvae developing at sea, but this has not been described for A. flavus.
In the aquarium
A sand-bottomed tank with space, a tight lid and live or frozen foods suits river gobies of this genus. The FishBase ranges above are a reasonable starting point. Use caution with small tankmates, since adults are sizeable and predatory on small fish.
Conservation
The IUCN assessed Awaous flavus as Least Concern in 2011, meaning it is not currently considered at risk.