Yes. The size of the anemone has to match with the clownfish hosting in it. A Big Clownfish hosting inn a Small Anemone will not work in most cases. Now the reverse instance is just fine.
If I were you I'd look for a RBTA (Rose Bubble Tip Anemone) for your little Nemo. My two Ocellaris Clowns originally hosted in the sand at night. Then all the frog spawn in the tank. Now they host in all the RBTA's in the tank, but it took some time before they figured that out. :
-David
40 Gallon Breeder on Steroids!!!
Where You'll Find An Acan, Dendro, and Orange Ricordea Garden In Bloom.