My goldfish has a yellow spot on nose is not eating,have given him Melafix for 3 days. I don';tknow the ammonia level nor the nitrate level,ph level is 7 .He is laying on the bottom of his five gallon tank. He is small and have air going in by a line. I know I should dispose of him,he is so weak, but as long as he is breathing, I will let him live. Hehas been goinh downhill for a week. Need some help on what to do.

Zena - you should really start testing the water in your tank. The majority of diseases/illnesses/problems occur due to bad water conditions. Is your fish on his own in this tank? You could do with posting your water parameters - either take some on your tank water to a local aquatic centre/shop, or buy the test kits and post the results on here so that we can advise you further.

Hi and welcome to the site.

I would suggest doing a 50% water change. What are you using the melafix for?

Do you have a filter on the tank?

As the above poster said you are going to need to test the water. Water quality is the most important thing to a fish. It can heal them or kill them.