Willito,
I think with Peppermint's that size shouldn't matter too much.
Instead it's more of a 50/50 when you buy a Peppermint shrimp because it all comes down to the region/local where they are collected from. Some reefs would have aptasia and others wouldn't, so it would be more dependent on the natural surroundings.
It's like lake trout around here, trout have a natural instinct to eat flies yet depending on the area, some may eat only black flies while others will eat strictly red stripped flies
