Nectogale elegans
Range
Sikkim and China (the source does not name Nepal)
The elegant water shrew, Nectogale elegans, is the only species in its genus, a shrew described by Henri Milne-Edwards in 1870. The source says it lives in Sikkim and China and does not name Nepal, so its Nepal status should be checked (Wikipedia, general species account).
The source gives no size, appearance, habitat, diet or behaviour detail (Wikipedia, general species account).