I'd leave adding small cichlids if you are to try it until the Vieja are much larger (of course not large enough to predate on them). A.Nanolutea aren't really able to put up with much aggression, the few times I've grown batches out they are quick to retreat and fail to flourish until removed. Shame because they are beautiful but their attitude and resilience isn't on par with other Amatitlania etc. The couple of pairs I kept live in a 240 with a few B.Smaragdina, L189 and a shoal of pristella tetras that I've nowhere better to place.