In a tank that small I would not put any others with it. You might be able to get away with a mid level swimmer or top water swimmer but I would not put more that one. I would choose 3-4 dwarfs and let the bonding develop naturally. Once you get a pair pull the others. The problems with dwarfs is they tend to be more aggro than the larger species, therefore you would likely have problems with conspecific aggression in a 29.
You might be able to house a bellycrawler in there with a mid water species or two just make sure they are not to small to be eaten.