I do not recommend "flicking" either I just wanted your opinion on it, because I know fishkeepers that do!

My opinion on it would be that it's damnned dangerous and not recommendable given how physically delicate fish are. I've recently seen it being mentioned one or two slightly less reliable websites, such a comment on a YouTube video and a Chinese fishkeeping forum with the occasional word of English here and there.

Can you provide any reliable sources where it suggests doing this? I would be very interested to see what the general attitude is towards this practise.