Like I said, the peacock is a no. Maybe you could keep it in there a little while but it will outgrow the tank fast. I misread yor first post too. It isa 12, not a 20
anyways a N. wennerae are generally recomended because they are easy to find, hardy and personable. Go to tampabaysaltwater.com and they cost 10$ plus 40$ shipping, BTW I love your sig! BOO PETA! (yay PETA, or "People Eating Tasty Animals"! )