Hi,
I've wanted to join the forum for a while and my sick goldfish prompted me to finally join. I have 3 comet goldfish that are about 2.5 inches in body length. They are in a 55 gallon (with intent of upgrading when they get bigger) and it has 2 filters and a few plants. Just a few hours ago I noticed that 1 of the 3 fish had a curved spine and was laying on its side on the bottom of the tank. It is still breathing and looking around and occasionally swimming around while its spine is still curved. The ammonia is between 0.25 ppm and the Nitrate is 20ppm. I was away from home for a while so they haven't had food in a 2 weeks and have been in the dark during that time.
I moved the fish into a 10g hospital tank with 5 gallons of new water and 1 gallon of old tank water. He has been swimming around a little more since going in there in the past 30 minutes. I am going to petsmart to buy meds tomorrow morning so I want to figure out what is wrong tonight hopefully. I have read people talking about ammonia or nitrate poisoning or bacterial infection. The other 2 fish are fine which makes me think it isn't the parameters.
Thank you for any help or suggestions! These fish mean a lot to me so I am trying to do as much as possible to help him.
Note: the image is him in a quickly put together hospital tank.