Do you want a hosting anemone (i.e., one that clownfish live in)? If so, I recomment Entacmea quadricolor, BTA. They are the easiest of the host anemones and are natural hosts to maroons, tomatoes, clarkii, among other species of clownfish. For a 29 gallon, you could have a nice display with E. quadricolor and a pair of clownfish. You will need intense lighting, T-5 fixture with 4 bulbs would be fine. You will also need to set the tank up and let it become established for 3 or more months before adding an anemone. Temp of 78-82 is good and specific gravity of 1.025-1.027. Regular water changes and the use of a protein skimmer and activated carbon will help maintain high water quality which anemones require. BTAs live on live rock, so you will need to provide that. They appreciate good water flow and powerheads need to have a screen to prevent the anemone from getting sucked in if the anemone wanders about the tank.