Ichthyological Research

, Volume 58, Issue 3, pp 288–290 | Cite as

A note on Aaptosyax grypus, a very rare, unique cyprinid fish

  • Yoshio Tomoda
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Rainboth (1991) described a new cyprinid fish, Aaptosyax grypus, from the Mekong River in Thailand, establishing a new monotypic genus. I was very interested in his figures of the species, which was similar to Chanos chanos in general appearance, and visited the fishermen’s base at Khong Chiam, eastern Thailand, several times from April 1998 to January 1999. Then I obtained a total of ten specimens of A. grypus: two from Khong Chiam and eight from the lower reaches near Khone Falls, Laos. All specimens were adult and larger than 700 mm in standard length (SL). One specimen was obtained in August (Khong Chiam), while the others were all obtained from the end of November to December, which may be the spawning season of the species, when the temperature of the Mekong decreases to 20°C, the coolest period (see “Ecological notes”).

Since Rainboth (1991) first described the superficial characters of A. grypusin detail, little biological information has accumulated for this species (e.g.,...



I wish to give thanks to Dr. Chaiwut Krudpan, who helped me a great deal when collecting specimens. Thanks are also extended to Dr. Katsutoshi Watanabe and Dr. Tsuneo Nakajima, who helped with the preparation of the manuscript.


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Copyright information

© The Ichthyological Society of Japan 2011

Authors and Affiliations

  • Yoshio Tomoda
    • 1
  1. 1.TakashimaJapan

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