Speaking from personal experience, I've got guppies and dwarf gouramis in the same tank. For a few weeks the guppies have suffered the occasional tail nip and, even though I've not witnessed the attacks I'm 99% sure it's a dwarf gourami doing the damage.y do you say no to the guppies? do they not go well with the gourami?
You could chance it and be fine, but if 1 of the gouramis takes a liking to the guppies tails then it will cause a lot of unnecessary hassle. Such as having to buy a new small tank to move the injured fish into for treatment.