Java fern is a very hardy plant and tolerant of different water chemistry which can vary depending on locale. Fish generally will be healthier and happier in planted aquariums … and plants act as a natural filter using carbon dioxide and contributing oxygen. Also plants utilize nitrogen in photosynthesis which in some forms is lethal to fish. Nitrogen is a byproduct of fish wastes.
Plant matter makes up a majority of the diet for a majority of tropical fish – many aquarists keep plant only tanks that are breathtaking and are often referred to as dutch aquariums. In Europe this type of natural aquarium is popular dating back decades.
Lighting is important and timers as well as carbon dioxide and plant supplements are sometimes very helpful
Ultraviolet sterilization can control unsightly and unwanted outbursts of microlgae or green water.
As for breeding most fish will breed naturally when they are healthy. Live foods help to condition them for breeding. Gouramis (a family of fish) are egg-layers and bubble-nest builders to be precise.
Often compatibility is an issue when creating a community aquarium – a larger tank will mitigate some of the territorial hostility. A well planted aquarium will provide lots of hiding places for the offspring of livebearers … egglayers are less likely to spawn and require more attention to detail and knowledge of nutrition and spawning triggers.
I could go on endlessly … so if you have any specific questions do not hesitate to contact me ….