Hi im new to all this. I was just looking for a little advice really I have a 125ltr community tank its been set up about 9 months now and had no problems but slowly my fish keep dieing iv tested the water and had it tested at my local store and reading s was perfect iv noticed they keep slowley start to stay in one place and not swim around and lose appitite I came home today to gind the angel fish swimming upside down a couple of others that died was slightly lopsided iv treated for white spot iv tried meth blue and anti internal bacteria I have done many water changes and still no joy..