Should i get more???

i have an opaline gourami, and what the lady said was anothr one(it doesnt look the same, i think its a dwarf) the opaline is really harming the other one... how can i fix this??? i heard that getting more females would help.... or to get some other kind of fish... perhaps an angel fish or a rainbow shark???? what do you recommend. its a 10 gall. tank it has a filter, heater, air stone with air pump, a cover and a light. it has rocks on the bottom, and some bamboo and a cave. do i need anything else??? it has the water conditioner and parasite clearer. i heard that the sharks go very good with the opalines, but i also heard that they are very difficult to keep alive. Help would be greatly appreciated!!!!