Question
I have a 200 gallon pond with 4 gold fish, the largest is about 4 inches long. How many gold fish can comfortably fit and thrive in the pond?  

Answer
In aquariums, they say at least 10 gallons per goldfish. For ponds, some say 100 gallons per goldfish but I think that's excessive.  I have about 30 goldfish in my 1800 gallon pond which is 60 gallons per goldfish.  So, I think for your pond, about 10 goldfish sounds right.  Of course, goldfish spawn like crazy so even if you started with a pair, you may end up with a ton!  I promote predators at my ponds to keep my goldfish population in check.  Good luck!

Robyn
fishpondinfo.com