I have a 75 gallon tank, includes 1 Nasa Tang, 1 Yellow Tang, 1 FoxFace, 1 damsel, 1 Flame, 2 dawrf angels, 1 manderin, 1 goatfish, 1 serpant star, 1 cc ship, 1 urchin, 1 crab, 1 conch, 2 snails, 4 clown fish. All my water conditions are testing perfect. About a week ago my goatfish stopped...