In the past day or so my Blue Gourami has swollen up on one side. I have had him for about 3 years now, and he is about 3-4 inches long. He has always been healthy as far as I can tell, and no other fish in the tank seem to bother him.
First off his color has faded some, and he seems a little lethargic. The left side of his body behind his gill and in front of his middle spot is swollen out in a roughly circular area and is about his body thickness in size outwards. His right side looks like it might be swollen also, but it is only a little if it is.
Here is a pic of him. Unfortunatly I seem to have trouble taking pictures of fish with my digital camera.
My primary concern is that 1. He is suffering and should be killed now and 2. He/she may have something that can hurt the rest of the fish in the tank.
Also of note is that the tank is about 3 weeks old and we have lost a few original fish after the transfer to it. The new fish we added are (Gold Gourami, albino Cori, Speckled Cori, 2nd golden Killi, 7 blood fin tetra, 2 spotted catfish, 2 high fin platti, 2 dalmation platti, 5 gold dust Moli). The new tank is just under 40 gallons.
First off his color has faded some, and he seems a little lethargic. The left side of his body behind his gill and in front of his middle spot is swollen out in a roughly circular area and is about his body thickness in size outwards. His right side looks like it might be swollen also, but it is only a little if it is.
Here is a pic of him. Unfortunatly I seem to have trouble taking pictures of fish with my digital camera.
My primary concern is that 1. He is suffering and should be killed now and 2. He/she may have something that can hurt the rest of the fish in the tank.
Also of note is that the tank is about 3 weeks old and we have lost a few original fish after the transfer to it. The new fish we added are (Gold Gourami, albino Cori, Speckled Cori, 2nd golden Killi, 7 blood fin tetra, 2 spotted catfish, 2 high fin platti, 2 dalmation platti, 5 gold dust Moli). The new tank is just under 40 gallons.
Have you checked the water stats? With so many new fish added you're bound to have a mini cycle going and since he's spent x amount of years in a mature enviroment the strain of new tank syndrome on him may be whats caused this. Sounds somewhat like he could have dropsyand that's not easy to cure. Are his scales sticking up at all? 
Wish I hadn't been tbh. 
Poor girl. Yes, get the ammonia and nitrIte readings down as much as pos and continue with small daily changes to keep the levels minimal. At a pinch it's worth getting some Bactinets (sold at a few of the larger fish stores in the UK now) to colonise your filter. I used them as a part seeding on my 100g when I set it up. I also moved one of my mature filters over to the tank alongside the new filter but the mature filter was originally running in a 30g so not nearly big enough for the new tank. As it is the bactinets worked very well. 
Another good thing to do is get bactieria from a current mature filter of course. Best of luck with the rest of your fish in there.
