Welcome to TONMO, the premier cephalopod interest community, and birthplace of #WorldOctopusDay and #CephalopodAwarenessDays. Founded in 2000, we are a large community of experts, hobbyists and enthusiasts, some of whom come together when we host our biennial conference. To join in on the fun, sign up. You can also become a Supporter for just $50/year to remove all ads and enjoy other perks. Follow us on Twitter for more cephy goodness.
We don't recommend dwarfs since they have a short life span and much of it is spent in their caves so you may not even see it that often. I think 30 gallons would be ok for one. If I can remember, www.caribbeancreatures.com has them.