One of my neons has a pretty distended belly. I thought maybe I was just overfeeding but I've switched to feeding only once every other day to see if that helps, but I've seen no change. Tank parameters are normal (nitrite, ammonia 0, nitrate 15 - lots of plants) and pH is 6.5 bc I filter with peat. Is s/he just fat? The tank only has some neons and cardinals (it's a 10 gallon) and the rest of the fish are normal sized. Thanks!