I still believe it's E.quad., but I can't say for 100% certain without seeing the pedal disk however, so .... maybe it is and maybe it aint
. You don't see purple too often in BTA's though, it is a rare morph. I have once seen a blue morph, I don't know if it was a natural colour or if it had help (dyed corals/anemones are a disgusting practise but it seems to still happen unfortunately
)