I have seen peps pick on a newly introduced Haddoni, and attempt to pick on a healthy one at night --- after the lights are off. If the Haddoni is hosting clown(s) the risk is less, but would still be there.
So, it is up to you if you want to take the risk, and there is no guarantee that the peps will go after the aptasia. I find using kalk paste to be more effective.