Blackmast, Craterocephalus stramineus (Whitley 1950)

Other Names: Strawman

Blackmast, Craterocephalus stramineus. Source: Neil Armstrong. License: All rights reserved

Thsi hardyhead is easily recognised by the tall first dorsal fin with a black leading edge. Blackmast often occur in shoals near the surface in areas with abundant aquatic vegetation.
Blackmast in the Finniss River near Batchelor in the Northern Territory.

Cite this page as:
Vanessa J. Thompson, Craterocephalus stramineus in Fishes of Australia, accessed 01 Dec 2023,

Blackmast, Craterocephalus stramineus (Whitley 1950)

More Info


Known only from the Ord River drainage, WA (128º33´E) to the Katherine River, NT and Gregory River, QLD (139º15´E). A tropical species inhabiting freshwater streams and lake margins with aquatic plants, often forming moderately sized shoals near the surface.


Dorsal fin VI-VII + I, 9-10; Anal fin I, 10-11; Pectoral fin 13-14; Vertebrae 33

Body compressed, robust; greatest body depth 2.9-3.2 in SL; mouth small, oblique, protractile; rear edge of jaw not reaching eye; ventral profile more convex than dorsal; one or more rows of strong teeth on outside of mouth; front of each jaw with a single series of pointed, slightly movable; vomer without teeth; nostrils small, oval.

Body covered by cycloid, slightly crenulated scales; vertical scale rows 27-31; scales present on head.

Two separate dorsal fins; 1st dorsal fin tall, much higher than 2nd; 1st dorsal fin with seven long flexible spines, its origin behind level of origin of ventrals, before level of vent, and much nearer snout than root of caudal; 2nd dorsal with one short spine preceding the branched rays, its origin behind level of that of anal; anal fin with 1 feeble spine and eleven branched rays; 2nd dorsal and anal rounded, not elevated anteriorly as in Pseudomugil; pectoral small, the third ray longest; caudal fin forked.


To 6.5cm SL, commonly to 4cm.


Semi-transparent with a pale yellowish hue; adults with a bright yellow ventral surface; mid-lateral stripe edged with silver or blue; fins mostly clear but front section of 1st dorsal fin black and outer edge of 2nd dorsal fin and anal fin yellow.


Omnivorous, feeding on small invertebrates and algae.


Pair spawning with a few eggs deposited into the vegetation each day. Eggs with adhesive filaments. Larvae hatch after 7-9 days.




Populations may fluctuate throughout the year becoming more abundant during the wet season when conditions are more favourable.

Similar Species

Easily distinguished from other species in the genus Craterocephalus by the tall first dorsal fin with its black leading edge.


The specific name stramineus is from Latin and means 'straw' in reference to the yellowish colouration.

Species Citation

Quiris stramineus Whitley, 1950, Rec. Aust. Mus. 22(3): 239 fig. 3. Type locality: 
Katherine River, NT.


Vanessa J. Thompson

Blackmast, Craterocephalus stramineus (Whitley 1950)


Allen, G.R. & Leggett, R. (1990). A collection of freshwater fishes from the Kimberley region of Western Australia. Rec. West. Aust. Mus. 14(4): 527–545

Allen, G.R., Midgley, S.H. & Allen, M. (2002). Field guide to the freshwater fishes of Australia.  Perth : Western Australian Museum 394 pp.

Crowley, L.E.L.M. & Ivantsoff, W. (1992). Redefinition of the freshwater fish genus Craterocephalus (Teleostei: Atherinidae) of Australia and New Guinea with an analysis of three species. Ichthyol. Explor. Freshw. 3(3): 273–287 [283]

Larson, H.K. & Martin, K.C. (1990). Freshwater Fishes of the Northern Territory. Northern Territory Museum of Arts and Sciences Handbook Series Number 1.  Darwin : Northern Territory Museum of Arts and Sciences 102 pp. (as Quirichthys stramineus)

Leggett, R. & Merrick, J.R. (1987). Australian Native Fishes for Aquariums.  Artarmon : J.R. Merrick Publications 241 pp. (as Quirichthys stramineus)

Merrick, J.R. & Schmida, G.E. (1984). Australian Freshwater Fishes Biology and Management.  Sydney : J.R. Merrick 409 pp.

Whitley, G.P. (1950). Studies in Ichthyology No. 14. Rec. Aust. Mus. 22(3): 234–245 figs 1–5 pl. 17

Quick Facts

CAAB Code:37246030


Max Size:6.5 cm SL


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