Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
That is typical behavior for Gouramis. They see the females as potential egg/fry predators. They see all other species of Gourami as competitors for their territory.
Some Gouramis are more aggressive than others. In a 55 you could stock 1 of the more aggressive types- 3 spot (or color morphs), Dwarf, Betta splendens, Paradise Fish. Some of these are so aggressive they will attack other species (non Anabantoids) that swim lower in the tank.
Moonlights, Pearls and Honeys are less aggressive (mostly) and you might try 1M + 1F of Moonlights or Pearls, or even 1M + 2-3F Honey Gouramis. Have lots of hiding places.
The other thing to consider about stocking fish is their requirements for temperature, water parameters, water flow and so on.