Fancy goldfish tank size question

[jas077]

Hey! I’m getting bigger tank for my fancy goldfish. I have read that with 1 fantail goldfish we need 80 litres/ 20 gallons but 120 litres/ 30 gallons would be better.

So how many litres I need if I add one more fancy goldfish?
( How many litres with every new added goldfish?)

 

[Aiken Drum]

Add an additional 40 litres/ 10 gallons for each additional goldfish.

 

[jas077]

Thank you!