The fly-specked hardyhead (Craterocephalus stercusmuscarum) is a species of fish in the Atherinidae family endemic and widespread in the freshwater streams of the Northern Territory down the east coast of Queensland into southern Queensland. It forms shoals in streams' shallows (both slow flowing and fast flowing). It grows up to 10 cm (usually 5–6 cm) in length. The Australian Museum has a sample taken from the Annan River in its ichthyology collection. The Museum describes the species as follows: Breeding and spawning occurs in October to February. Males gain a bright yellow or gold belly for the occasion. Females deposit large, transparent eggs onto aquatic plants. Larvae 4.8 - 6.4 mm long hatch after 13 days.