Hey everybody, Recently I upgraded my tank to a bigger 90L tank for my angel fish and 6 tigger barbs they were fine for the first day but then i noticed that my 2 angels started acting like they were blind bumping into everything and just acting strange. I did another 50% water change and then took a sample of my water into the local pet store for testing. They came back and said that my water is too hard and gave my some crushed oyster shells to put in the filter, unfortunately I lost my precious white angel fish this morning and my black angel is still acting strange and not eating at all. Does anybody have any advice for me ?