Help identify this.

[Dizzy]

Hi. Hoping someone can help.
I've noticed these stuck to the glass since adding some fish and a new plant.
I've looked in threads, and it would seem they're a harmless limpet.
Can anyone else confirm this, and put my mind at ease, it is it more sinister?
Kind regards

 

[G H Nelson]

Yes, looks like it!

What is that?

Hi all ☺️ I just saw this thing stuck on my tank’s glass, looks like a snail but only.. flat. My only guess it’s a limpet but not sure. Whatever this thing is.. is harmful? If it is not harmful is beneficial? If yes, what does it do? Sorry for really bad quality photo but iPads really don’t...

www.ukaps.org