Hucho taimen (Mongolian postage stamp)

  The taimen (Hucho taimen), also known as Siberian taimen and Siberian salmon, is a species of fish in the salmon family (family Salmonidae) of order Salmoniformes.

• Series: Fish
• Country: Mongolia
• Year: 1965-11-25
• Emission: Commemorative
• Perforation: comb 11
• Printing: Photogravure
• Size: 43 x 43 mm
• Face value: 20 Mongolian möngö 
• Number of catalogue Michel: MN 401

Acipenser baeri (Mongolian postage stamp)

  The Siberian sturgeon (Acipenser baerii) is a species of sturgeon in the Acipenseridae family. It is most present in all of the major Siberian river basins that drain northward into the Kara, Laptev and East Siberian Seas, including the Ob, Yenisei (which drains Lake Baikal via the Angara River) Lena, and Kolyma Rivers. It is also found in Kazakhstan and China in the Irtysh River, a major tributary of the Ob. The species epithet honors the German Russian biologist Karl Ernst von Baer.

• Series: Fish
• Country: Mongolia
• Year: 1965-11-25
• Emission: Commemorative
• Perforation: comb 11
• Printing: Photogravure
• Size: 43 x 43 mm
• Face value: 15 Mongolian möngö 
• Number of catalogue Michel: MN 400

Brachymystax lenok (Mongolian postage stamp)

  Brachymystax lenok, the sharp-snouted lenok, is a salmonid fish distributed in rivers and lakes in northeastern Asia. It formerly included the blunt-snouted lenok, but recent authorities typically treat the latter as a separate species, B. tumensis, based on differences in morphology and genetics.

• Series: Fish
• Country: Mongolia
• Year: 1965-11-25
• Emission: Commemorative
• Perforation: comb 11
• Printing: Photogravure
• Size: 43 x 43 mm
• Face value: 10 Mongolian möngö 
• Number of catalogue Michel: MN 399

Siniperca chua-tsi (Mongolian postage stamp)

  Siniperca chuatsi, the mandarin fish or Chinese perch (not to be confused with the mandarinfish), is species of temperate perch native to the Amur River basin and other rivers in China. Its back is yellow, green, or brown, with many irregular black spots and patches.

• Series: Fish
• Country: Mongolia
• Year: 1965-11-25
• Emission: Commemorative
• Perforation: comb 11
• Printing: Photogravure
• Size: 43 x 43 mm
• Face value: 5 Mongolian möngö 
• Number of catalogue Michel: MN 398