Today I found one of my Oto's dead in the tank. The tank has more than enough algea in it and my Oto's all appear to be healthy and eating well. When I found this Oto this afternoon, it's stomach was huge. This happened to another Oto of mine about 2 months ago. When it happened to the first one I just kind of dismissed it since I know Oto's are sensitive but after this occurence I decided to look into it. I found that many people report having their Oto's die with similar circumstances. Those being an aged tank w/ good chemistry and on a sufficient diet w/ no previous signs of distress. My tank has been cycled for some time and my reading today were pH 7.6, Alk - 0ppm, Nitrite - 0ppm, and Nitrate - 5ppm. Didn't check hardness. I'm wondering if any one has a clue as to what this could be. IMO it's belly was huge, too huge. What could that possibly translate into?