Can some aerators not come out?

[Coraline D]

Hi,
I’m looking at removing an aerator to install a filter on the tap in my bathroom.
I’ve been trying with a sticky pad and pliers and it’s not budging whatsoever.
Not sure if i’m doing it wrong (mainly trying counter clockwise to get it off, tho tried clockwise at some point too out of desperation).
It looks like it should come off from the sides but maybe it actually doesn’t ?
Any advice ?
Thanks so much for the help
Pictures coming up

 

[gmartine]

Usually just screws in and is removed by turning counter clockwise. May have flats for a spanner or knurl to grip or both.

 

[Ben-gee]

There’s no picture?
If there are flats on the sides it should come off with a spanner, counter clockwise.
Some now seem to be screwed up inside the spout, these require a special plastic key - very similar to a football stud key.
This will have been supplied with the tap but they often go missing.