in 20 tall with 30 watts i would say no for two reasons.
1 tank is entirely to small for an anemone while it might be ok at first soon as it got healthy it would out grow the tank really fast. (Stack a bunch of boxes up in your closet to resemble your LR, put a 30w light bulb in the fixture and close the door. this is how the anemone would be living)
2 even if you have 30w t'5s (i dont even know that they make them) 30w isnt enough for an anemone. They feed off of light they would not get nearly enough off of that. You would see it turn whiter and whiter all the time and eventually die of starvation. Probably fairly fast as most anemones i see at LFS's are already bleached to some extent.