My Goldfish :(

Question
My tank has been set up for over a year now, its about a gallon or two I am not sure on the exact size. I have two comet goldfish, I don't have a filter just am airpump. I am not sure about the pH, ammonia, or nitrite levels. I used to change they water whenever it got dirty however one fish recently just contrated a bacterial infection and I was told to change the water everyday for two weeks, by taking out 10-15% of the water and filling it back up with fresh water. I also was told to add an antibacterial thing to help my fish, my fish with the infection is cured, he's been better for a few days now, but my other fish is now acting funny. He is curled over and only using one of his fins, and barely moves his tail. He stays underneath his rock which he never used to go in. He eats very little and only moves if I talk or lightly tap the tank. Any insight to what could be wrong and what I can do to help him would be wonderful thank you!

Answer
Hi Jamie;

The tank is just too small for goldfish to live a very long life. Each goldfish needs 10 gallons and good filtration because they get so big (6" and up) and are just messy guys by nature. Here is a good web page about them so you can get your next goldfish tank properly set up;

http://www.firsttankguide.net/goldfish.php

At Your Service;
Chris Robbins