Which snail is this one?

[Aietes_Ch]

Hi there
I've ordered online two Cerithium echinatum (Cerith Snails), to help my 8-gallon nano reef against some Cyanobacteria (but there there are also some Dinoflagellates).
However, yesterday I have received two snails and to me they are clearly not Cerith Snails! Unfortunately I have no clue what they are. Cannot find a picture of them in any books or in internet with convicing clue about what they are.
They are small (about 0.7 in), opercolated, with a nice zebra pattern. They tend to rest going up to the water border, sitting slightly outside the water. They seem to graze on algae, and they haven't yet disturbed the tank corals (mainly soft corals).
Any idea what they could be? Any chance they can survive? would they feed on cyanobacteria?
Thank you for any help.

 

[ISpeakForTheSeas]

I'm not very good at snail ID, so hopefully we'll get some other eyes on this for you, but possibly Littoraria scabra or Planaxis sulcata? These are both considered herbivores if it's either of them.

 

[Aietes_Ch]

Thank you!!!
Based on the base opening, and the internal kurling, I would consider more likely Planaxis sulcata
However I do not find any information on the size, which would have further confirmed this.
See if we get additional ideas on these.

 

[damsels are not mean]

It's definitely a member of the periwinkle family. All of those are herbivores to my knowledge.