Perhaps this is also true of Bitaeniatas. Therefore, there could be some significant color variation within a population but this is a product of selection, as you suggested above. Even the Amazon is not a uniform environment, there exists many barriers to small fishes like apistos that inhabit side tributaries and creeks, such barriers restrict migration and gene flow. Therefore, I think most of the variation we see in Apistogramma is between locally unique populations that have become isolated through time, genetics and the everchanging meanders of the river, rather than within one immensely variable super population. Alenquer aggasizzi One of the most beautiful of all A. agassizii varieties.
Adults become metalic blue on body, deep yellow or orange on belly.
There is a red variety, meaning more red on caudal fin, than the normal type. Not difficult to breed. Very colorful population of A. geisleri. Chest emerald-green, usually with red markings. A species from the A. regani-group.