I was painting some underwater artworks for office work last 2 weeks and jellyfish wasn't in any of it. So, I decide to paint it on my free time. Upon looking at a few images, I believe jellyfish can be paint with just a round brush with brush tip blend mode set to "screen".
VideoThe painting process took around 30 to 40 minutes. Took a bit more time as I was experimenting a bit on how to approach the painting.
ArtworkThis is the final artwork which I have upload both in my pixiv and deviantart.
Youtube Lets Paint Glowing Jellyfish