i have had in the past 2 pearl gouramis, and the slightly larger 1 kept on harrasing the slightly smaller 1....eventually the larger gourami thrived and the smaller one slowly deteriorated and died....i still keep the surviving pearl gourami in my tank with tiger barbs and an angelfish and all is doing well....
And to you plant question, plants benefit all fish you have in your tank and if you add alot, imo, it will limit how many fish you can have in your tank....same goes with the decorations...a tip. buy plants that would need the same requirements your fish would need....buy some plants that your fish would live with in the wild so they could become more comfortable with their surroundings...also, if your planning a high tech planted aquarium, add a nutrient rich subtrate under your chosen gravel/sand before you buy any fish or plants.....You can put the sunken ship as a decoration and a place to hide in but using driftwod would give you tank a more natural look....
