They're not really that aggressive but they can be very nippy. Individuals sometimes school with swordtails, platys and mollies. Overall i think they are easy to keep. They're quite popular as feeder fish where i'm at
yep , they are very hardy and prolific fish. mine just keeps giving birth. I recommend keeping them with their own kind because they are sometimes aggressive and their tankmates would be outcompeted for food.
to be successful,you just need to apply the same care with guppies. good luck.