The natural hosts for ocellaris are:
Heteractis magnifica
Stichodactyla gigantea
Stichodactyla mertensii
Of the three, you may see magnifica (ritteri) every once in a while. Gigantea are somewhat rare, though I've seen quite a few lately. Mertensii are very rare.
All are considered "expert only" given their inability to successfully adapt to captive life. Most ship poorly and must undergo a long acclimation process. Once through this process though, they can be hardy, assuming tank conditions are stable. All get very big and I personally recommend nothing smaller than a 100 gallon tank, though you may be able to get by with a 60 gallon if you have a small specimen.
Judging by your photo, it looks like your tank is relatively new (no coral, no coralline or other growth on your rocks -- which don't appear to be live rock). If you're interested in getting an anemone, the general rule of thumb is to wait at least 6 months.
As already suggested, bubble tip anemones (Entacmaea quidadicolor) or BTA for short, are a very good beginner anemone because they are very hardy and can tolerate different tank conditions related to flow, light, and water parameters. However, they are natural hosts for most sebae or clarkii type clowns, as well as Premnas (maroon) and mixing clown fish species is not recommended.
Finally, it looks like you have at least four clowns in your tank. This will be fine for the short term, but they may eventually end up pairing up, and will beat up the ones that are left out.