Yes you can have peacocks. How many would depend on what you want though. If your interested in breeding, only one species per tank, most females look the same so once mixed you can't tell which species is which. If you go all male, you can have one multiple, but none that resemble each other, so one red, one blue, one yellow and some smaller haps to finish filling the tank. The all male tank can take awhile to get right, so you'll need extra tanks and a place to get rid of fish that don't work out.