How many gallons does the tank they are going in hold? I do not advise females as you would need ALOT to balance out a 5 male ratio correctly, we are talking a minimum of 15 females although 20 would be a safer bet to spreed out agression, and thats if you have an empty cycled 30-40gallon tank minimum to put them in. You would also have to then deal with the huge quantitys of fry they produce.
The best way to stock all-male group is to stock is slowly, lets say we have an already cycled tank; start with 2 males in the first week and add one more after the first week. Study their behavior and see who is the most agressive, you may have to take out the most agressive male, add one more based on if they are not been agressive to each but add 2 more if they are being agressive to each other- add the last male if you only added one last time after another week. This process gives you more time to exchnge any agressive males and the slow stocking process helps the males build a more stable pecking order between them.
You could get away with putting them in a 10gallon tank, but a 15-20gallon would be better as the extra space will help avoid conflicts between the males and give any who get picked on alot a decent space between their harrassor/s. If you go for a 15 or 20gallon tank it would be good to add some other types of mid to top level dwelling fish as these will help distract the males from each other- making sure the tank has plenty of planting and hiding spaces for the fish is also important to avoid agression and over bullying from the males.
