It is a Heteractis Malu. They’re notoriously difficult to keep.
Under blindingly bright lights they’ll be a pale greenish tan colour, but under anything less than the sun they tend to fade to pale. Whatever luck you have with it is anyone’s guess but I wouldn’t buy another. Bubble tips are the safest bet and usually maintain better colour under moderate lighting.
5 weeks in though it’s looking happy enough, just watch out for it wandering and a tight mouth is generally a sign of a happy anemone.