Craterocephalus stramineus (Whitley, 1950)
Blackmast

Family:  Atherinidae (Silversides), subfamily: Craterocephalinae
Max. size:  6.5 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater; pH range: 7; dH range: 12
Distribution:  Oceania: endemic to Australia.
Diagnosis:  Distinguished from all other species of that genus by a combination of the following: greatest body depth 3.1-4.1 (3.8); least body depth 8.0-9.9 (9.2); origin of pectoral to anus 2.8-3.1 (3.0), all in SL. Eye 2.6-3.5 (2.9) in head. Dorsal process of premaxilla 1.4-2.2 (1.8) in eye. Lips in premaxilla 2.6-3.7 (3.1). Predorsal scales 10-12 (10.9). Origin of first dorsal from one scale behind to 2.5 scales in front of tip of pectoral fin (Table 1). Unique in dentition and length of spines in first dorsal fin. Differs osteologically from other members of the genus by a combination of the following: shape of premaxilla and maxilla; lateral ramus of premaxilla with greatly reduced secondary process; shape of nasal bone; and with basibranchial toothplate present. Differs genetically from other species only in allele frequencies at the following loci: FUM, MDH and MPI (Ref. 26703).
Biology:  Occurs in clear, flowing streams, as well as in still water. Found in well-vegetated stream and lake margins. Forms moderate-sized shoals, swimming just below the surface (Ref. 44894). Feeds on insects and their larvae, small crustaceans, snails and some algae. Although attractive, they are delicate and usually difficult to maintain in captivity (Ref. 44894).
IUCN Red List Status: Least Concern (LC); Date assessed: 15 February 2019 Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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