Yes, Rams are a dwarf cichlids. Bolivian rams are the hardier, but harder to find ones. German Blue Rams, Gold Rams, Black Rams/Dark Knight Rams/Black Knight Rams, and Electric Blue Rams are all the same species, the Venezuela Rams. They're more delicate than the Bolivian Rams are. Apistogramma are also a nice choice in dwarf cichlids, but much harder to find than the Venezuela Rams. The easiest Apistogramma to find is the Cockatoo Dwarf Cichlid, or the Apistogramma cacatuoides, it's also the most forgiving of the Apistogramma. If you want something hardier, you can try Julidochromis, Either Transciptus or Gombe, they're small enough for a 20g tank. Multis are much harder to care for, they need sand and snail shells big enough to hide in, though they're the smallest cichlids in the world, the males being just under "2, and can be kept in a 10g if necessary. Kribensis might also be okay in a 29g, but they can get aggressive during breeding. Though, all cichlids are generally aggressive when they've got eggs/fry. In my experience, the Julis are the least aggressive when it comes to protecting their young. They'll protect the rocks that is their territory, eggs and fry included, but once the fry get big enough they'll chase them off, or some might be allowed to stay and help care for their younger siblings. I've seen Kribensis fry eat their younger siblings, and the parents just ignored it. All of these cichlids will stay on the bottom. I once had Cacatuoides in a tank with guppies, and they all got along well enough, even when the Apistogramma spawned. Guppies stick to the top of the tank, Apistogramma to the bottom.