Sevenspot Archerfish, Toxotes chatareus (Hamilton, 1822)

Scientific name: Toxotes chatareus
Alternative name/s:
Common Archerfish , Spotted Archerfish
Sevenspot Archerfish, Toxotes chatareus Click to enlarge image
A 24cm long Seven-spot Archerfish from the Australian Museum Ichthyology Collection. Image: Mark McGrouther
© Australian Museum

Fast Facts

  • Classification
    Genus
    Toxotes
    Species
    chatareus
    Family
    Toxotidae
    Order
    Perciformes
    Class
    Actinopterygii
    Subphylum
    Vertebrata
    Phylum
    Chordata
    Kingdom
    Animalia
  • Size Range
    The species grows to about 40 cm in length.

Introduction

The Sevenspot Archerfish feeds primarily on swimming and floating insects. The archerfishes (family Toxotidae) are well known for their ability to shoot down resting insects by spitting a jet of water.

I.20453-005 - Toxotes chatareus
The mouth of a Sevenspot Archerfish, Toxotes chatareus. Note the groove along the roof of the mouth and the shape of the tongue. Archerfishes have adaptations to the mouth which enable them to accurately spit a jet of water to knock insects out of overhanging branches. A deep groove runs along the roof of the mouth. A ridge along the top of the tongue fits into this groove. When an Archerfish shoots a jet of water, it raises its tongue against the roof of the mouth forming a tube. The gill covers are then quickly closed, which forces water along the tube. The tip of the tongue acts as a valve. Image: Mark McGrouther
© Australian Museum

Identification

The species has a variable colour pattern. The body is typically white or silvery, with six or seven black spots of varying size. The dorsal profile of the body from the tip of the snout to the dorsal fin is almost straight. This body shape in combination with the location of the dorsal fin well back on the body, allows the fish to swim very close to the surface and look upwards without creating surface disturbance. This is an advantage when hunting insects which rest on overhead vegetation.

Habitat

The species lives in freshwater and estuarine habitats.

Distribution

The Sevenspot Archerfish is found throughout much of south-east Asia. In Australia it is recorded from Derby, Western Australia to Townsville, Queensland.

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

Feeding and diet

Sevenspot Archerfish feed primarily on swimming and floating insects. The archerfishes (family Toxotidae) are well known for their ability to shoot down resting insects by spitting a jet of water.

Other behaviours and adaptations

The Sevenspot Archerfish can spit accurately to a distance of about 1.5 m. It has adaptations to the mouth which enable this spitting ability. The lower image shows the deep groove which runs along the roof of the mouth. A ridge along the top of the tongue fits into this groove. When a Seven-spot Archerfish shoots a jet of water, it raises its tongue against the roof of the mouth forming a tube. The gill covers are then quickly closed which forces water along the tube. The tip of the tongue acts as a valve.

Life history cycle

Merrick and Schmida (1984) stated that "Preliminary studies on Northern Territory populations indicate that there is no sexual dimorphism; maturity by both sexes is attained at a length of approximately 200 mm, weight of 250 g to 350 g and age between one and two years".

References

  1. Allen, G.R. 1989. Freshwater Fishes of Australia. T.F.H. Publications. Pp. 240.
  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. Merrick, J.R. & G.E. Schmida. 1984. Australian Freshwater Fishes. Biology and Management. John R. Merrick. Pp. 409.