This a long shot but you can try a methylene blue dip. It helps with ammonia and nitrite poisoning.
Use as a Dip
You can also use Methylene Blue as a dip for treating fish with fungal infections, those affected by external protozoan parasites, or those suffering from cyanide poisoning.
- Prepare a nonmetallic container of sufficient size to contain the fish to be treated by adding water similar to the original aquarium.
- Add 5 teaspoons (24.65 ml) per 3 gallons of water. This produces a concentration of 50 ppm. It is not recommended that the concentration is increased beyond 50 ppm.
- Place fishes to be treated in this solution for no longer than 10 seconds.
- Return fish to the original aquarium.