No. Depending what you want. You must do it on start. I have player/enemies always on top (every tick), so I must move on top what I need. But this I posted working well, I am justing it right now and looks cool. Just need good tweaks depending on game window resolution, enemy size in pixels etc, so you must try yourself.
Here sample, it looks better when animated and you can tweat particles shape, sizes etc for smother effect.
Edited, you not need to move particle top if you add particle after object enemy to project - particle will be over enemy always.