Backyard Aquaponics
A place to discuss aquaponics

Hey Guys!

My system includes; one fish tank - BLC (1000L / 264 gallon) and three growbeds - 1085L / 286 gallon total. 4 weeks old and after two weeks started with 35 fish, added 20 more today for a total of 55 goldfish pond.

I weighed one (average is 6-10 cm long), it was 12 grams.
It's approximately average of the tank, which means 12 (g) * 55 (fish) = 660 grams of fish in total. Calculated with the rule: 1 lb of fish per cubic foot of bio media. I get 15.75kg fish, which I am far from (660g), as goldfish grow slowly I've heard.

So... am I *frack*(meaning wasted money on wrong fish)? Or have I missed something?
Is it enough to run my system?

forgot to mention that all growbeds is filled with gravel

From what info I have gathered, safe stocking capacity in an average system could be from .63 lbs to 1.56 lbs of fish per cubic foot of wet gravel. This is total FINISHED weight of the fish and this is if you feed them at a rate of about 2% body weight per day as adult fish. This is if you have:

1) fish tank water exchange of 1 - 1.5X per hour.
2) adequate aeration
3) removing fish solids and uneaten food.

.63 lbs/cu ft is if you have only #1
.94 lbs/cu ft is #1 + #2
1.56 lbs/cu ft is #1 + #2 + #3

Here is a site that gives the number of goldfish per pound depending on the size of the fish.

http://www.ozarkkoi.com/Goldfish-Weight-Goldfish-Information-sc-97.html

In my system they grew to about 5-6 inches in a year.

And here is a good video on stocking densities.



https://www.youtube.com/watch?v=IPEFlhRBaQI

Thanks for input!

Let me see if I got it right:

I have 38 cubic feet of wet gravel and #1 + #2 (0.94 lbs per cubic feet).

38 * 0.94 lbs = 36 lbs

Then I need: 36 lbs / 16 kg in my system.

My fish is now 1.4 lbs / 0.66 kg.

From my calculation I need way more fish, correct?

Jeff you had a space before the video link