I've had two species of clown mate in my tanks, Clarkii (wild) and 2 different pairs of False Percula (Wild and Tank Raised). They have all EVENTUALLY hosted in BTA's. The tank raised ones can be stubborn. I know the ones we get from ORA are funny about this. I'll put them in our tanks at the shop, and the next day 3 or 4 may be in an anemone...while other times I order them and no clowns touch an anemone for weeks!! Part of it may be maturity...in all my cases with clowns, I have found that after they have concretely established their mating pair, they will look for something to host in; this is instinctive, tank raised or not. I would recommend keeping with Bubble Tips, and to be patient, it may take a year or so for them to really settle into being a proper "pair" of clowns.