Backyard Aquaponics
A place to discuss aquaponics

Hello from the States,

Wintery Ohio to be specific.

We have 2 water gardens at our place and I am thinking about converting the one to growing fish for our consumption. The magazine on the front page has an article where the author harvested 100 KG of veggies and 50 KG of fish.

My question is how many KG of fish food does it take to get 150 KG of food for human consumption?

We have beef, hair sheep, chickens and bees on the farm now I am looking at fish. Raise a lot of our own vegetables and can them. Make our own sauerkraut every year. (Like to know what we are eating don't you know!!)

So what ratios have you experienced?

Food to FIsh to Veggies??

Thanks in advance for your help.

You can get as much as 10 times the weight in veggies as the weight of the fish. However, I think much of that depends on what you grow. Some plants take a lot more nitrogen that others.

Welcome ONG!

What part of Ohio? I am from Lancaster originally. I love sauerkraut but no one else in our family likes it. More for me on New Year's!

Howdy Dave,

Holmes County where all the Amish and furniture manufacturing is. Draw a line from Cleveland to Columbus and we're about 1/2 way.

Great!

I haven't paid any attention to my feed ratios; I am just happy that they don't die and are getting bigger. Currently I can't feed mine like they want to eat because they are in the basement with no plants to remove nitrates. We are kind of stuck with seasonal production due to temperatures and light slower down the system during the Winter. It would be a fight to keep things moving throughout the Winter in our climates, even in a greenhouse.

Feed ratios are going to vary by species, but fish is much more efficient that most other animals. Fish produce about 1 pound body weight for every 1.5 - 2 pounds of feed for an experienced aquaculturist. I suspect I do a bit worse; maybe 3:1. I haven't been tracking it.

As folks point out, the veg produced can be much more than the fish. And of course, there's the value of a pound of iceberg lettuce as opposed to the value of a pound of fresh basil in the dead of winter.

Oh, and to answer your question more fully. Let's be conservative, and assume 3kg feed produces 1kg liveweight of fish. Most fish dress out into fillets at about 33%, so we'll use that. Then let's take DD's 10x factor veg:fish and cut that in half, again to be really conservative.

So 1 kg feed=
333g liveweight or 111g boneless fillet plus
1666g veg =
1777g or 1.777KG total of food

Doesn't seem fair that I should get more than I put in, does it?

Therefore, if I wanted to produce 150KG of food, I must use as input 150/1.777 = 84.4KG of food (plus sunshine, water, chelated iron, and good husbandry.)

JP, that is great information. On the 3 kg feed to produce 1 kg of liveweight fish, is that over the fish's lifetime? So, if a person started with fingerlings, they could plan on feeding them the 3 kg over their life to get 1 kg of live fish? "Their life," of course, being from fingerling to harvest.

I am thinking about keeping a tank full of crawdads. If I can feed the 2/3 of the fish that is wasted to the crawdads I should be able to lower my feed to food ratios.

Yep! oh and welcome ONG

Healingdeva, yes, that is over the fish lifetime.

oooo...crawdad waste processing. So then we take the 2/3 of the fish that isn't fillet, and turn that into crawdad, and they have an FCR of..... wait a sec, you're trying to make me write a recursive routine. Not gonna happen...go do yur own math.

Then, of course, there are the worms you can feed with the vegetable waste (vermicomposting) and then feed to your fish for part of their food. More out of the system for less into it... Or, the duckweed and/or azolla you can raise on the fish effluent and then feed back to the fish as part of their food... The circle gets better.

For us - the scraps are going to the chickens...

How do you "process" them before feeding to the chickens?