This video is about European weatherfish, Misgurnus fossilis.
It says about itself:
New small Misgurnus fossilis, 1½ – 2½ days after hatching 01 06 2014
The first days after hatching the new Misgurnus fossilis (European weather loach) just are “hanging around” in algae, sediment a. s. o. Later they will be more active and be looking for food all around in the fish tank, prepared weeks ago to make the water alive/to contain first food.
Translated from the Dutch RAVON ichthyologists:
Tuesday, May 19th, 2015
Hedgehogs, rats and herons like eating European weatherfish, which is evident from transmitter research by RAVON. This loach is also high on the menu of the purple heron in the Natura 2000 area Zouweboezem. It was suspected that the northern pike, the main freshwater predator fish, also likes to devour weatherfish, but evidence for this was lacking, until …
Recent research in Hungary (pdf, 0.4 MB) shows that in water with a big weatherfish population, the diet of pikes in the spring may consist for more than 90% of weatherfish. Probably the nocturnal loach, which normally hides during the day, during the reproduction period is easy prey as they swim along the banks by day.
Recently, also in Brabant province in the Netherlands, proof was found of a northern pike eating a weatherfish.