Today my Green Terror and yesterday my Texas have been swimming awkwardly and erratically in circles, upside down, sideways and everywhich way, as if they were in pain. before this tarted they were doing fine then all the sudden became very dark in color and were almost motionless. they would swim around once in a while. So today I was doing a 50% water change on my 55 g tank. I ahd already taken the texas out of the tank for the crazy swimming and today my GT started to do it during the water change. I put him in the hosptial tank with the texas to continue to chane the water. I was wondering if this is just a stress response or if it is a sign of parasites or if it was water quality. I have also noticed scales from the fish lying in the bottom of the tank and my dempsey is flicking his pelvic fins up and down rapidly If anyone else has experienced this or knows what this is caused by please help!