this is one of those situations that you will have to keep a very close eye out. When the Oscars reach sexual maturity, they can often become very rough with each other, often causing quite serious injuries. The best advice I can give you is to monitor the situation, if it becomes obvious that they are fighting all the time then you may have to split them up. If they do hang around each other and seem to get on, then just give them time. Serious signs of aggression are flaring gills, lots of jaw locking and injuries caused on a regular basis. You might find the fish will avoid each other in the tank if there is a serious problem between them
