Black goldfish turning white

Question
We have a black goldfish and up until today was acting fine but tonight, after a warm day, we noticed that "he" was 1/2 black and the other 1/2 greyish white.  He was acting weird and I also noticed that there was some film floating around.  I have since cleaned his bowl (1.5 gal.) and filled it with cool water and put chlorine neutralizer in it.  We were gone for the weekend and I'm wondering if we may have over-fed him.

Answer
Hi Miriam,
Please let me apologize for not getting back to you. I feel so bad. But lets get right to it.

Since your Goldfish lives in a bowl he likely turned white due to pollutants in the water building up. The small water volume in the bowl means waste is going to build in just a matter of even hours. Goldfish really don't do well in a bowl at all. They are very prone to health problems and are short-lived. The white may be a coloration change due to stress but it could also be a fungus patch. Fungus can attack fish if the water is not clean enough for them.

If it the white patch looks like slime of a little bit fuzzy most certainly it is fungus. I've had the best luck treating fungus with Jungle Brand's Fungus clear which you can find at WAL-MART of local petstores.

This problem may keep re-occurring if he continues to be exposed to dirty water which is almost impossible to avoid whenever you have a bowl. If you could get him into a 10-gallon tank with a simple power filter this is a very inexpensive setup that although not ideal for goldfish it is a million times better than a bowl.

Also, if he does have fungus and you do have to treat him. Along with the fungus medication make sure you change his water everyday (about 50% or more) and redose the medication. This really helps cure fungus.

Best of luck and I hope all is well!
Karen~