I got about three different types of julies in my tank, various sizes and amounts of each. They can be really aggressive to new tank mates and anything smaller than them. They are really aggressive to own types and less but still aggressive to other julies...
They like rocks and places to hide, shells will work when small as well, but small reefs with open places to swim work... Build up with rock and they will stay off the bottom all the time. Often mine swim upside down at the top of the tank at feeding time when they are little to eat some flake... when larger they will eat pellets fine, they enough brine and worms as well...