I Have had two gold fish for about two years.
One is smaller than the other.
I was told how to clean the tank, which is very small, big enough for two fish not needing a pipe or anything.
The pet shop man told me to keep a little of the old water each time cleaning it and then to refill the tank with fresh filtered water and I use anti cholrine soultion.
On Friday September 23rd September they were fine. On Saturday the big one had completely disappeard?
I emptied most of the water and refilled the tank but I didn't clean out under the stones like I normaly do. The water has been muggy and dirty beofre but they have still survived.

Where could the big fish be?

Did you check the area around the bowl on the floor?

I have had fish jump out of a tank before.

More then likely the other fish ate it.

Non chlorine solution?? What are you cleaning your tank with? You shouldn't be using any type of cleaner to clean the tank.. You get a cyphon and clean the gravel. Use a scratchy pad made specifically for glass or acrylic to clean off the algea on the sides of the tank.

Another note. Goldfish don't do the best in a glass bowl. They need filtration and heat and space. You should upgrade them to a 10 Gal. Most 10 Gal start up kits come with everything you need for about $50 buck max.

Is there anything else in the tank besides the 2 fish?

I once moved one of my comets (5 inches long) to a bucket and put a board over the top so nothing could get to it and proceeded to clean the pond. When I went back to get the fish it was gone.:eek: