Over the last few weeks my pearl gourami as been sitting at the bottom of the aquarium not doing so well. It hardly moves unless it's eating and when it does it swims kind of bent. It looks like it's getting smaller because my second pearl gourami looks like it's much larger and they were once roughly the same size.
I don't have much to say, without more info, but it could be a swim bladder problem. It could be getting skinnier because it's having a hard time swimming to get food, or an internal parasite could be stripping it of nutrients and damaging the swim bladder organ. It really could be lots of things, unfortunately. I would keep a closer eye on it, for other symptoms, and really rack my brain on any new items, fish, plants, anything that you might have added to the tank recently that could carry something, or give you an indication of what it could be. I am sorry your gourami is not feeling very good, hopefully you can figure something out soon and help to treat it. Good luck.