I have a 38 gallon fish tank with 2 silver dollar fish, 2 clown loaches, 3 kuhlI loaches, 1 common pleco, 2 giant danios, 1 Raphael Catfish, 1 lace catfish, 2 quary catfish, 1 betta fish, 4 skirt tetras, and 2 angel fish. I bought 14 neon tetras. All my neon tetras died, my pleco (got dropsy), 1 kuhlI loach, 2 quary catfish, 2 clown loaches, raphael catfish all died. My silver dollars have moth fungus, my 1 angel and skirt tetras have fin rot. My skirt tetras had ick. I have a gravel fish tank. I got melafix and tetra ickgaurd I wasted both medicines. I bought new hang on back filter and new heater. The heater killed the ick. I still have fin rot and mouth fungus. I added some API aquarium salt very little. Now what should I do?