Fish names of Mongolian lexicology as a field of study received little attention in the past. It has become the focus of linguistic concern in the last few decades. The present study is intended as a comprehensive survey of a significant part of the Mongolian lexicon. 70 Mongolian fish names from wutiqingwenjian are phonetically and semantically investigated and compared with that of Manchu and with the contemporary docu-ments, i.e. Mongeoyuhae and Hancheongmungam. The conclusions are summarized like followings. 47 Mongolian fish names are mostly no correspondence with those of Manchu. 7 names are revealed loan translations. 3 terms are partial substitutions and 13 names are loanwords. Hence it is a scholarly contribution to research on Mongolian lexicology. Focusing on a language contact, this study is also a contribution to the field of contact linguistics.