I purchased 5 blue gouramis Saturday from the LFS. I took them home and put them in my aquarium. Later that day I noticed one of then has a problem. The black part of the right eye is smaller than the left eye(which looks normal compared to the other fish). It is obviously different. I didn't notice this at the store when I got the fish. The fish is not as active as the others and seems to swim a little leaning to the left. He is eating with the others however. I called the store and told them. They said they didn't know of any disease that would cause this and I could bring in a water sample because it is most likely a water problem. I checked the PH and ammonia myself. PH is 7.5 and ammonia 0. The water temp. is 78. The tank also has 7 mickey mouse platies.This is a new 55 gal. aquarium. It was set up and running for 3 days before I added the fish. I treated the water with Tetra Aqua Safe and used wardley PH down to lower the tap water PH from 9.6 to 7.5.The other fish are all fine. I am puzzled. I think the fish may have been physically damaged either being netted or during transport. It's been almost 48 hours now and the fish shows no change(for better or worse) in condition. I am concerned I might loose the fish. If anyone can help I would really appreciate any feed back. I have been keeping fish for about 5 years. This is my first experience with gouramis.