I would try a trio of Kipli or mpimbwe. wild caught. they are the most prolific and mild tempered. Again, it is a gamble with such a small group and tank. The male very well may decide to kill the female. colder temp like 75 degrees will help with aggression and breeding. dont really need a bunch of hiding places, a couple flower pots will help but too many rocks will sometimes cause eye damage if being chased. My WC never use caves