You have a parsite problem. The hole would indicate that. The bulge in the belly would indicate an internal infection. Vita-chem is only vitamins. Try Metronidazole and Nitrofuranace or Clout i'd look to water quality. You don't say what other fish you have in your tank? I would quarintine this fish and treat with Metronidazole and Nitrofuranace or Clout When yo0u say whater is fine, i assume you mean
ammonia 0
PPM,
nitrite 0 ppm and
nitrate 20 ppm or less, higher values stress out fish and allow parasite which are always present to overcome stressed fish. You can also try this, change out 25%-30% of your tank’s water and premix 4-5 tablespoons of aquarium salt to the new water before adding this back to the aquarium. hope this helps