It totally depends on the age of the swans. If they are younger swans, they will get along fine as they may even pair up (which is exactly what happens when an opposite gender mate is not available for young swans). If the swans are juveniles or younger, there should be no problem especially, since the lake is of such a great size.

Now, having said this, if they are older swans or if one becomes extremely territorial during mating season, then, you may have a problem. But, if they can get along for a couple of seasons, then, they should not have a problem later in life. The Regal Swan