Guppies and some other livebearers are okay at room temperature tanks.
Other coldwater fish like goldfish need three years to mature, and white cloud minnows usually don't eat all their eggs or babies so long as it's a species-only tank (meaning even scavengers/algae eaters are a no-no.)
A severe lack of trichogaster.
Just because your Gourami is sick does not mean it is always Iridovirus, DGIV, Gourami Disease, et cetera.
Look at all the other factors in your tank before coming to this conclusion.