chrissaysyes
Nereus
Well, a 30 gallon would be much better, and much easier to keep up with. For one thing, there's no garauntee that your clownfish is going to host whatever anemone you choose. There are a lot of sites (and theres a chart here somewhere) which have charts that will give you an idea of which clownfish host whichever species of anemone naturally. A Condylactis or Hatian would be good and hardy but clownfish dont host those in the wild. Your hardiest and most likely candidate is probably a Bubble Tip Anemone. Find one that's captive bred as it will be much healthier and hardier.