This video is called European weather loach, Misgurnus fossilis, “chewing sand”.
Translated from the Dutch RAVON ichthyologists:
Thursday, November 27th, 2014
The weatherfish has been found again after 20 years in the Drentsche Aa river area. A single ranger was still able to recall that this loach species occurred about 20 years ago in the catchment area of the Drentsche Aa. Since then, attempts to see the fish were always unsuccessful. On the basis of DNA testing it could be demonstrated that the species fortunately is still present in the area.