|MadSci Network: Zoology|
Vibration of the body is a feature of courtship in many species of fish. If you make a more generalised search for information, rather than focusing on lumpfish which are a northern deep-water marine species and less likely to be closely studied and filmed, you will find numerous examples of this behaviour. Try entering "fish vibration" in YouTube, for instance.
Try the links in the MadSci Library for more information on Zoology.