Not for very long. Since goldfish are extremely high waste producers, a smaller body of water would slowly kill them due to the toxins and lack of oxygen in the water.
No. Like all members of the carp family, goldfish can survive in a wide range of water temps.
Salt water, water that is too hot or cold or has chemicals in it
No, absolutely not! Brackish water has salt water in it and it will die because of that!
Goldfish are very hardy fish and can survive a wide range of water conditions. It wouldn't surprise me if they were the last fish to die after a major tank/water problem.
Sea water with some bacteria in it. (That's what they eat.)
Goldfish need water to swim and breath in, not mud. There are some species of fish that have evolved to survive in mud but Goldfish are not one of those species.
Some species of goldfish can survive in 0-degree water, but most goldfish won't survive in water below 10 degrees C. The fish would probably survive a while but would eventually stop moving and die.
goldfish will survive in tap water but it is best to put a bit of chlorine control in the water plus you will need a filter if you want the water and tank to stay cleaner for longer :)
No, goldfish are best with goldfish with the exception of weather (dojo) loaches, bristlenose plecos, and apple/mystery snails.Although goldfish can survive in warmer water temperatures, they are a "cold water" fish and not a tropical fish.
to survive in shallow water
In nature there are many kinds of tiny macropods, microscopic algaes and other things in the water when goldfish breed in spring under normal/wild conditions. These 'baby goldfish foods' can be purchased at most good pet shops
They have shallow roots that grow right under the water.