I find any deep bodied species of fish are good tank mates for pike cichlids.
If the fish are tall, the pikes ignore them, as they are to high to be prey
The dither or target species you choose just needs to coincide with size your pikes will eventually get, and water parameters your pikes need.
Both species above, the pike and Guianacara, being from the equatorial area of Amazonia, appreciated soft, low pH, and warm water parameters.
In the tank below (a Uuguayan community), the pike and others from the temperate area far south of Amazonia, are species that tolerate a wider range of parameters, and water temps
Tetras that would work, (as moneioned above) would also need to be more high bodied and large enough species.
There are hundreds from South America, just avoid the longer, more cylindrical, minnow types if you don;t want them to become expensive feeder fish.
