Most of the time tenuis and vermiculata are dang near impossible to tell apart, there are some things you can look at to make an educated guess though-
vermiculatas radial corallites calice rim more often comes to more of a point rather than being more rounded/ cup like that tenuis usually presents, however tenuis can exhibit this as well, its usually more prominent on vermiculata though, vermiculata will also sometimes have shorter axial corallites, the final and probably most reliable differentiating factor is that vermiculata's radial corallites will have more of a rasp like arrangement as opposed to tenuis rosette arrangement, which is what I am seeing on the coral in question.
Id agree with
@SBB Corals on this probably being a vermiculata .
Beautiful piece!
