Care on Sebae Anemone

[Tennyson]

Lately I have noticed how nice Sebae Anemonies were and wanted to buy one. But I heard that they are very hard to take care of. Why is that?

I have T-5 lighting for a 46 gal tank. I have a Bubble Tipped and two Haitin Reef Anemonies that cant move (I put them in conch shells, and they like it and stay put, but just for the Haitin Reefs).
And there are three clownfish that host the bubble tipped and I plan to get a Sand/Rock Anemone and Anemone Shrimps and Crabs.