I had a hell of a time with male gouramis beating up on my females when I started stocking my 2nd tank. I started out with 2 males and 1 female, and the largest male spent virtually all day chasing both the other male, and the female around, so after a few days I took him back and got another female, which gave me 2 females and 1 male, and all was fine. A few days later the remaining male began to chase around and beat up both females, and after 2 or 3 days of this both of the females fins were looking very ragged, and neither of them had eaten much, or at all for a few days, as they were always hiding from the male, so I ended up taking that male back and getting another female.
This kind of leads into a question I have: Is my 25 gallon tank too crowded? In it I currently have:
2 female opaline gouramis
1 female gold gourami
1 female pearl gourami
1 female silver gourami(Just added today)
7 peppered corydora catfish
1 clown pleco(Just added today)