Zero, goldfish need very clean cool water and are very dirty fish.
A fish bowl is not a solution its what you keep your goldfish/ beta fish in :P
it depends how big the fish bowl is
just a normal bowl from the local pet store or wal-mart i believe has them. they are just a medium bowl that costs about 5-15 dollars depending on what size you want. When i had gold fish i had 2 as well and i liked to give them space. it is your choice.
If it is as old as a goldfish that can, it can.
The cheapest way to keep a goldfish is to keep it in a fish bowl.........as long as the bowl is big enough the fish will be happy there.
small fish
if your gold fish is small or medium fedd 3 to 4 small gold fish food
Bowls are not meant for fish. 1. all bowls are to small. 2. no filtration. Well..this is correct, but you can have a Chinese fighting fish without filtration but only one per bowl.
Yes, provided the bowl is large enough.
A fish needs 20 litres in a bowl
Yes, like all pet fish, goldfish need more oxygen than can be provided by just a bowl of water.
The water in a goldfish bowl should be changed at least once a week to maintain the health of the fish.