Animal Species:Giant Squirrelfish, Ostichthys japonicus (Cuvier, 1829)

The Giant Squirrelfish can be recognised by a combination of characters that include its red colouration, deep body, large eyes and robust ctenoid scales. The Giant Squirrelfish lives in deep marine waters.

Giant Squirrelfish, Ostichthys japonicus

Ian Merrington © Ian Merrington @ DPI Fisheries

Standard Common Name

Giant Squirrelfish

Alternative Name/s

Japanese Soldierfish, Japanese Squirrelfish

Identification

The Giant Squirrelfish can be recognised by a combination of characters that include its red colouration, deep body, large eyes and robust ctenoid scales. It lacks a strong preopercular spine. When viewed from above there is a broad V-shaped gap between the bones of the snout. This is the premaxillary groove.

Size range

The species may grow up to 41 cm, but is most commonly approximately 20 cm.

Similar Species

A second species of Ostichthys, O. kaianus is also recorded from Australian waters. It can be separated from O. japonicus by the number of scales along a straight line between the lateral line and the middle of the spiny dorsal fin (2.5 versus 3.5 in O. japonicus). O. kaianus also has an Indo-West Pacific distribution, but in Australia is only known from off the north-west shelf of Western Australia.

Distribution

The species is known from scattered localities around the Indo-West Pacific. In Australia it is found on the north-west shelf of Western Australian and off central New South Wales to eastern Victoria.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums.  Source: Atlas of Living Australia.

Ostichthys japonicus

Distribution by collection data

Ozcam map of Giant Squirrelfish specimens in the Australian Museums.

What does this mean?

Habitat

The Giant Squirrelfish lives in deep marine waters (90 m to 194 m) and is sometimes caught by anglers and trawlers.

Classification

Species:
japonicus
Genus:
Ostichthys
Family:
Holocentridae
Order:
Beryciformes
Class:
Actinopterygii
Subphylum:
Vertebrata
Phylum:
Chordata
Kingdom:
Animalia

What does this mean?

References

  1. Gloerfelt-Tarp, T & P.J. Kailola. 1984. Trawled Fishes of southern Indonesia and north-western Australia. Jakarta: Directorate General of Fisheries (Indonesia), German Agency for Technical Cooperation, Australian Development Assistance Bureau. Pp. 406.
  2. Hoese, D.F., Bray, D.J., Paxton, J.R. & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.
  3. Paxton, J.R., D.F. Hoese, G.R. Allen & J.E. Hanley. 1989. Zoological Catalogue of Australia Vol.7 Pisces Petromyzontidae to Carangidae. Canberra: Australian Biological Resources Survey. Pp. i-xii, 1-665.
  4. Randall, J.E. & D.W. Greenfield. 1999. Holocentridae: Squirrelfishes (soldierfishes). in Carpenter, K.E. & V.H. Niem (eds) FAO species identification guide for Fishery purposes. The Living Marine Resources of the Western Central Pacific. Vol. 4. FAO Pp. 2225-2256.
  5. Randall, J.E., Shimizu, T & T. Yamakawa. 1982. A Revision of the Holocentrid Fish Genus Ostichthys, with Descriptions of Four New Species and a Related New Genus. Japanese Journal of Ichthyology. 29(1): 1-26, pl. 1-2.


Mark McGrouther , Collection Manager, Ichthyology
Last Updated:

Tags Fishes, Ichthyology, Giant Squirrelfish, Ostichthys japonicus, Holocentridae, red, deep body, large eyes, robust ctenoid scales, deepsea, marine, Japanese Soldierfish, Japanese Squirrelfish, 10 cm - 30 cm,

5 comments

Mark McGrouther - 8.01 AM, 31 January 2012

S'weed, you have outdone yourself! The photo is fantastic and by examining it, I can tell you that the fish is not a Deepwater Squirrelfish. The premaxillary groove (the slot above the upper jaw) is not 'triangular enough' for the fish to be a Deepwater Squirrelfish.  The roughly parallel sides of the premaxillary groove and 'jagged' anterior margins at the front of the groove are characters of only one fish, the Rough Squirrelfish, Pristilepis oligolepis.  This species is recorded from the region.  Thank you so much for adding the images to the site.  At some stage soon I will add them as photo assets with a link from the Soldierfish page.

S'weed - 7.01 PM, 30 January 2012
Hi Mark, That description of O. kaianus certainly fits the appearance of the fish that I caught. I read online somewhere that captures of O. kaianus have been recorded in the Arafura Sea, and interestingly, my specimen was caught in particularly warm water for southern NSW; (22°C, by the temperature sensor on our sounder). We ended up keeping the fish, as it was suffering from severe barotrauma... I've attached another photo of it, which confirms the presence of a triangular feature on the top of its head. Cheers, S'weed

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Mark McGrouther - 4.01 PM, 30 January 2012

Hi S'weed.  What a fantastic image and comment.  Thank you for posting it.  I think that your fish is probably a Deepwater Squirrelfish, Ostichthys kaianus.  This is very interesting because Deepwater Squirrelfish are not 'officially' recorded from New South Wales waters (although we have a specimen from northern NSW in the fish collection).  Of course it is not possible to say for sure but the reasons for my decision are as follows.

1. Colouration.  When fresh, O. kaianus is "red with a series of silvery white dashes forming longitudinal bands on the body". O. japonicus, which is recorded from the region however is "edges of scales red, the centres silvery pink" - clearly different to your fish.

The third species known from Australian waters, the Spinesnout Squirrelfish, O.acanthorhinus is only known from northern tropical waters.  The other species you mentioned, O. archiepiscopus has not been recorded from Australian waters.

The only other fish that this could be is a species of Pristilepis.  This genus can be ruled out if your fish has a triangular space into which the upper jaw slots when the mouth is closed. See this image to get a better idea of what I am talking about.  Please let me know If you can confirm that the front of the head looks like this.

Reference:
Randall, J.E. & D.W. Greenfield.  Holocentridae in Carpenter, K.E. & V.H. Niem (ed). pp 2422-2524, 4 figs In The Living Marine Resources of the Western Central Pacific. Vol. 4. FAO species identification guide for Fishery purposes. FAO.

Mark McGrouther
Fish Collection manager.

S'weed - 10.01 PM, 27 January 2012
Can you please help me identify the species of Ostichthys that is in the attached photograph? Below are some details relating to the fish, which may be of relevance. • Caught 14/01/2012 at Sir John Young Banks, NSW, in ~16m of water. (On the drop-off from 8.5 fathoms; in the vicinity of 34°56.970' S, 150°54.820' E.) • Fork length approx. 31.5cm. • Looks similar to O. archiepiscopus, except that the discrete white spots along its body (one on each scale) are small in comparison to the scales, and do not form thick and relatively continuous white bands such as those seen in O. archiepiscopus and O. kaianus. • Scales rough, and also bearing very fine filaments reminiscent of glochids. (Filaments embed in skin upon handling of the fish, causing subsequent irritation).

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