Hey there, anems are not easy or hardy. If you have a very well established tank (like a year old) and it is very well lit, then anemones are possible. (although most still have problems with them.) Bubble tips are probably the most forgiving species of anemone, people even claim to be able to keep them long term under PC lights. (but they have to feed them like crazy). The feeding pollutes the water and the polluted water kills the anemone.
If you would like to keep an anemone in a small tank like that, try looking for a long tentacle plate coral (fungia). Not exactly the same thing, but similar looking and much hardier. Or some hairy mushrooms or a euphyllia (frogspawn, torch, octopus coral).
If you are dead set on getting an anem, look for a larger tank setup (anems get about a foot across often in less than a year.) And make sure you have a good skimmer and halide lights. Do some reading about the types of anems and peoples success with them. the anem and clownfish forum is a great source of info. You will see lots of threads about "my anem doesnt look so good" and the person posting gets bashed for not doing their research first. ('anemone police' like to fly off the handle when people do the things 'they' used to do.)
Not trying to tell you what to do, just passing down info I learned along the way.