Clownfish do not host anything that you want (ich, brook, velvet, and other parasites use them as a host).
Clownfish associate with anemones in the wild, and anemones host the clownfish. Most clownfish will eventually associate with any host anemone, but the process is usually sped up when the natural host is provided. Problem is, the natural hosts for ocellaris and perculas are the most difficult to keep for most.
I'd suggest trying a bubble tip anemone to start with, as they are a good first anemone. Keep in mind that the clown does not need an anemone to survive or thrive in captivity. Before getting an anemone, research the care requirements and know what a healthy specimen should look like.