Hi, I've got an oscar in a 200 gallon 6ft x 2ft x 2.5ft or something like that with a green terror, jack dempsey and a red terror. He is the biggest probably about 5 inches with the rest being like 4 inches and the green terror being like 2 inches. I just noticed him in the last 2 days twitching his side as if its irritated and then scratching on the bottom a few times with a fast burst but i only saw that once. Also he didn't eat anything this afternoon but did a long skinny poo that looked like a white/clear colour which was different from the normal which is whatever colour his pellets are usually. Im not sure if this is anything but some help would be good please i don't really want to lose him. The other fish are all happy and healthy looking, i saw the green terror do a little burst of speed scratching on the gravel but thats about it, the other fish are happy as ever.