Goldfish are best with goldfish with the exception of weather (dojo) loaches, bristlenose plecos, or apple/mystery snails.
You should not keep a fire belly newt with goldfish as their needs are very different. In addition, the newt needs a land area, so a smaller tank with partial water and a nice dry land area is best.
Not for long. The newts will poison the water for the goldfish and the poisoned water will kill them. There is a basic rule that amphibians should not be kept with fish under any circumstances.
Yes. As far as I know they can live together in ponds, so why not in tanks?
if they are in a proper tank
depends, can a ten gallon tank live in a goldfish
Yes
Goldfish should only live with goldfish with the exception of weather (dojo) loaches, bristlenose plecos, or mystery/apple snails.
You should not have goldfish and platies in the same tank ever.
Goldfish are meant to live in cold water, not the warm water in a tropical aquarium. This is a huge reason why goldfish and tropicals shouldn't be in the same tank.
yes and no it depends
Yes, but your tank size needs to support it. If you mean that a regular goldfish is a long single-tail goldfish, then you need at least a 40 gallon tank just for the 2 fish due to the size potential of the common goldfish. If you mean a regular goldfish as in a round bodied fantail, or perhaps a ryukin, then you need at least a 30 gallon tank for the 2 fish.
No newts need to be able to get out of water. I would put gavel in the bottom and some rocks for them to climb on and hide under. Then have water an inch or two above the gravel not the rocks though
as far as i know yes,unless your fish is aggresive
err not a good idear yabbies will eat a goldfish