While I have no exp. with these, a 29 gal. tank isn't going to cut it. Just google pictures/video of Heteractis magnifica aka Ritteri in the wild and you will quickly see that they have the ability to get over 3ft. I would try and exchange it for a BTA if you want a host species of anemone. Heteractis magnifica NEEDS Strong lighting, strong random flow and "perfect"/stable parameters for it to be happy. Hopefully others will respond who have exp. in keeping them long term.