Okay so previously I was having problems in my betta's 5 gallon tank with ich, I have gotten rid of this (at least I thought i had) with treatment and thorough cleaning and water changes and got myself a new betta. At first I had him with 3 ghost shrimp that I didnt think would be a problem but since they have disappeared I believe that he has eaten them (not sure if that effects my problem or not) and now after owning him for about 2 weeks, his right eye is extremely swollen and white, I believe this is called Pop eye, but am not sure if it is from an injury or another infection in my tank. It is only one eye so that is why I am not sure. He is eating but is about 50% as active as he was when I first acquired him. This tank is not filtered so I do frequent 25%+ water changes, there are live plants in the tank, and at times I run a small bubbler. It is extremely frustrating because I have no problems with my 2 large tanks, which Ive had for years, but this small tank has had alot of problems in the short time I have had it. Previously my roommate had the betta in a half gallon bowl and he seemed perfectly fine for over a year, but I felt bad for him and wanted to give him an upgrade, though it seems I have done more harm then good. Any advice on the pop eye, and smaller tank maintenance would be appreciated.