I have three young Electric blue Acaras in my 55 with zebra danios and tiger barbs. The goal is to get a mated pair and then rehome or put the remaining Acara into a community chiclid tank.

I bought them in two stages, a larger one from pet supplies , and a small pair from a family owned LFS. I believe the larger one (2") is male, with a small tassle coming off his dorsal fin, but the other two are still too small to tell (1.5"). One of the small pair is light-colored, and the other is remarkably darker, with a fully black face.

The large one and the smaller dark one often swim together and generally don't do anything when they see each other. If the small light-colored one comes out from behind the plants and is spotted by the large one it will sometimes be chased back into hiding. The small dark one doesnt really react to the other's presence. I've seen all three of them digging in the sand.

DISCLAIMER: all three of them eat together just fine. I've seen fish being bullied into the corner before, and the small one does get to come out and play more than one too stressed to leave the corner.

Tl,Dr: Do Acara pairs stick together and chase the outsider, or do the males chase the females into hiding? What if the big one is actually female?