I have had a few of these over the years. They are notorious for just letting go and floating into the water. Where they get sucked into your pump and shredded into little slimy bits that rot fast and cloud the water. I have lost all 4 this way. Once it caused a tank crash because it shredded it into pieces in the power head and just rotted as I was away at the time.
With that being said they do like a mature tank with lots of light and flow. They tend to stay put longer if they have host clowns in them and are getting high enough light, flow and food. But sooner of later they wander and like to pick spots you don't want them. Like at the base of your sps where it stings it or behind your rocks where you can't see it. I have never been able to keep one longer then 2 years. They have all wandered on me and let go and got sucked up. I will see if I can find a pic but the last one I had was massive. I am talking 25% of a 180 massive as they get really big. My advice is if you want a nem get one of the others like a flame bubble.
Magnifica naturally host I think 12 clown fish species so do a quick google to see what ones. As not all clowns will go into them. I personally like a larger clown in them as they get big. Something like a Cinnamon clown pair (Amphiprion melanopus) Or a small group of skunk clown. With a adult male\female and a few juveniles. Space permitting.