My atlas says the second one, Notho. Guntheri , is realatively aggressive. So you may want to consider keeping killis in a species tank. I was thinking about getting killis, but they are short lived, annual fish. Some are more difficult to take care of than others. Try this web site, it has lots of helpful info http/www.aka.org/
These were the ones recomended for beginers, and crossbreeding is cautioned against.
Aphyosemion australe
Fp. gardneri
Nematolebias whitei
N. guentheri and N. korthausae
E. sexfasciatus and E. fasciolatus