Yes, (but you didn't ask if it's a good idea, or if it's bad for the fish)
It is important to remember to put things in a goldfish tank, even goldfish get bored. Some of my suggestions for tank decor are artificial plants and a "hidey hole" for your goldfish.
about half an hour to an hour
No. Unless you put it in a tank with sand.
yes, but it may kill the goldfish
godfish can be any color-not just gold. yes u can put them together if they r the same breed (goldfish)
If there is water in there...
Borneo suckers.
Goldfish just need a plain bowl and some plants
you put it somewhere where there is no sunlight or light because goldfish die in the heat so use cold water and put it somewhere cold but not that cold
No. The only thing that can go into a 1g tank is a betta, and that's barely okay. PLEASE don't put any number of goldfish in a 1g
Enough salt and it will kill the fish
I really would not put the tadpoles in with the goldfish...the goldfish will most likely eat them all. It depends on the goldfish size, but eventually they will try to eat the tadpoles whether they suceed or not. :/