Hi Everyone, I am a newbie with an urgent problem. I have a 30 gallon freshwater tank (about 6 months old) with very good water parameters. All of my fish are about a quarter in body size. I have 2 blush angels, 2 discus, & a veil tail. The tank has been a happy peaceful home for most part. A bit of sparring periodically. Three days ago one of my blushers suddenly flopped at the surface several times and then zipped madly around the tank for 3 -4 seconds. It seemed to be out of control. Between these episodes the fish seemed fine. Yesterday the same thing happened. Today it did the same thing except except when the zipping was over the fish floated to the bottom. I saw it was still breathing so I waited and watched for a minute or so and then it got up from its side and swam away. The fish looks fine but I know it's not!