You can have really nice reef set ups! check out kidninja's nano thread, (there's some others out there too, but I can't recall any names). I'm 90% sure they do not come with skimmers, but on a tank that size it's pretty easy to keep up with water changes (1-2 gallons a week). The only thing you may want to consider adding is a small power head (koralia nano would work great, or if you have the money, an mp10. Though, judging by the flow I get from my mp10 in my jbj 24, I feel it would be a little powerful for the 12gal, but I've seen them on smaller setups). I personally really like the jbj nanos and think they're a great way to get into the hobby, but also really fun for seasoned veterans!
