I believe that they do because their gills take in oxygen and the filter would help generate the oxygen.
No, but it helps them live longer and healthier.
Your goldfish will not live "longer" no matter how many or how few you have.
Yes. A goldfish can live without a filter. They may not live as long, but they do not have to have a filter, or a heater. I had goldfish in a five gallon tank without a filter for a long time. Hope that this helps.
No bettas live for 2 years. goldfish live for long as 25 yaers if conditions are clean.
well it just depends how old it is
if the tank has a filter than yes but if it doesn't it cant live with out one.
For a few days yes.
You need a lot of things, unless you are raising goldfish in a bowl. You need: (for a tank) A filter A tank (not recommended under 5 gal.) Goldfish food Gravel Live or fake plants (underwater plants) Air pump (not required) Choice of decorations These can be very expensive sometimes, but it will keep your goldfish living longer and happier than in a bowl
fresh water
A little less longer than regular goldfish.
They don't have to have one but it's better for them and they will live longer if you do.
If it is a small goldfish, it will physically fit in something that small. But, it will not live very long in it. If you wish to keep goldfish alive, you need at least ten gallons of water for each goldfish along with a good filter and a heater to keep the water temperature stable. With proper care goldfish can easily live 15+ years.