How Many Gallons For Common Goldfish

How many gallons do you suggest a common goldfish live in. I've heard so much about this topic I would like to hear more opinions. I'm wanting a common goldfish. The only tank I have right now with nothing in it is only 170 gallons. I want to know if I can keep a few common goldies as I know they hate being alone. (I do bI weekly/daily water changes for all of my fancy goldfish.)

 

Honestly, they shouldn't be kept in an aquarium. They should be in ponds because they get the size of adult koi. I'd say in a 170 would maybe be okay for one.... At least from what people told me when I looked into getting one. But I have seen some HUGE commons, so I believe them.

 

You could probably do two. I know you're an experienced goldfish keeper, and honestly I don't see a problem wih that. I've seen 125 gallons for the first + 50 for each after, so that basically works.
Potentially you could have three, but that might really be pushing it

 

I personally think 170g is enough for a couple/trio. I've never found my goldies to be massive poop machines, but would encourage good water flow due to them being active fish.

 

I vote for 3. If you have a plan B down the road, maybe 4 definitely no more than 5.

Good luck!