Help sick fish

[Rebeccam]

I came home to see a nasty ulcer on my gold fish, right under his tail near his bum, he cant swim normally and swims upright (tail at the top of the tank and head down) his usually a very active fish but isn't moving much. I thought his floating might have something to do with food so I tried feeding him peas but he just won't eat. All the water levels are perfect I had them utested this morning. And there is another fish in the tank but he is healthy and him self. I attached a photo of the ulcer, the (string is a poo)

 

[NeverFadeAway86]

im not sure what could cause that. Is there anything in the tank with sharp edges ? that doesn't look to good for your poor fishy

 

[FreshyFresh]

Sorry about your issues. What size tank? What else in the tank and what is your weekly water change amount? Most issues like this are due to water quality issues. You should have your own liquid test kit for ammonia, nitrite and nitrate as well. They can be had for $20-30 and last years.

I wouldn't worry to much about feeding, but would be concerned with keeping pristine water parameters. Keeping nitrates as low as possible.

 

[Gregg]

I second water parameters as a starting point.
-Near 0 Ammonia/nitrite
-Low Nitrates
-Steady pH
-KH over 100 ppm for goldfish
-Balanced Redox

As for treatment; I would start with a fish "swab" using Methylene Blue then go with a medicated fish bath that includes salt/NaCl, Methylene Blue, Nitrofurazone, Kanamycin, & NaCl

An in tank treatment might be in order too. I would suggest a Medicated Wonder Shell for this.

Ref.
http://www.aquarium-pond-answers.com/2009/07/fish-baths.html
http://www.fishbeginner.info/home/what-makes-a-healthy-aquarium-or-unhealthy/