How many goldfish is to many?

[420benz]

I have a 725 Gal.pond 2Ft Dp. with 3 waterfalls, 2 bubblers and two canister filters.Also a large UV light.
So how many goldfish will this pond support? Thanks

 

[Lisak1]

I like this site:

Koi Length and Weight - Ammonia Produced, and Waste Produced

This chart also lists koi weight by weight and how much ammonia and waste they produce. Koi get heavier as they grow and produce more ammonia and waste.

russellwatergardens.com

They explain that total water volume is just one factor. The bigger issue is how many fish can your filtration support. UV lights mean nothing in this equation, and waterfalls and bubblers are about the same. Great to have, but if you don't have the appropriate filtration it won't matter.

 

[420benz]

These are my filters.

 

[jgrandmont]

I know the usual rule of thumb for tropicals is 1 inch of fish per gallon of water. I also know that goldfish are "messy" and produce more waste than tropicals. Following...

 

[Relic]

The simple answer is: The number of goldfish you want to watch in your pond will be too many...

 

[Gordo33]

Start with a minimum number and be patient because they will multiply. Then let your pond tell you what it can handle. You can test your water and look for signs like increased algae, how the fish are reacting, etc
6 years ago I started with 8 and now have over 60 . I don’t see as many new ones in last two years so I am assuming the fish are keeping the population down

 

[gwbasley]

725 gal. is a good size pond and one thing to keep in mind is that Goldfish will grow bigger in a larger volume of water. We have a 400 gal. pond with a bio filter and a small bog plus two waterfalls with spillways and it supports 8 (large) goldfish and one turtle. If you don't get the heavy monsoon like rains like we have here in Florida, you should pump down and add water, by about about 1/3rd, several times a year.

 

[Lisak1]

Goldfish will grow bigger in a larger volume of water.

Myth #1 - "fish will grow to the size of their environment". Sure, you can stunt the growth of a fish in a too small container, but healthy fish will grow to the size their genetic make up pre-determines, regardless of the size of the pond. Same as any other animal on the planet.

you should pump down and add water, by about about 1/3rd, several times a year.

Myth #2 - "water changes are necessary to pond keeping". I can tell you that many here - myself included - never do water changes in our ponds. Heavy rains may replace water, but I'd never pump my pond down to replace water intentionally. Pond water matures - the older it gets, the better it is. Adding "new" water can be stressful for your fish and can start a cycle of algae growth that's not desirable. Stability in a pond is the goal. Now if you've been doing water changes and that works for you, great. It's just not commonly promoted in pond keeping as an "absolute must do" like it once was.

The "inch per gallon rule" is another carryover from aquarium keeping. As you can see from the chart I shared, the difference between 30 inches of goldfish and a 30 inch koi is dramatic!

 

[addy1]

I do not water changes, except if it rains hard. Never have in the 11 years it has been running, no issues.
My fish have a big pond they have not become huge shubunkins, the biggest is around 10ish inches.