Backyard Aquaponics
A place to discuss aquaponics

I have looked at various links and they all say different things.
I am very confused about the ratio to square footage to pounds of fish.
Help is appreciated
DTA

Hi DTA, welcome to the forum

There is a lot of information out there and some of it is just plain wrong. See TCLynx first post here and it should help - http://www.backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646. There are roughly 7.5 gallons per cubic foot (in case you need this). Start with about half the max amount of fish and you'll do fine. It's harder when you are pushing the limits. You might want to look at fishless cycling the system before adding your fish but it can be done either way if you're careful.

Take a look at the IBC of Aquaponics (free to download PDF) - http://ibcofaquaponics.com/
I think it has some information on stocking levels but it's a good read and has some useful tables and other information.

Cheers

So, according to TCLynx's post, 30 Kgs of fish, per 1000 Liters of fish tank, is not too dense?

These figures are referring to your ending weights at the time of harvest - the maximum would be 30 Kg per 1000 liters (roughly 66lbs in 260 gallons for those on the English system - about like having 13 to 14 5lb catfish in an IBC tank). The fish aren't starting out that size. You can only achieve this if you have enough filtration and aeration and honestly I don't recommend trying it because you have tighter tolerances, it's more work and a lot more that can go wrong. These are just guidelines to help people get an idea of what will work. Starting off we usually suggest about half of the maximum for a finished weight so maybe you'd grow the same 14 catfish to 2.5 lbs instead of 5 lbs each.

Aquaculture grows fish at much higher densities than this and some types of fish do better than others when conditions are crowded (like Tilapia).

First, my apologies to DTA for hijacking his thread. That was not my intention.

Thanks. Yeah, I figured it would be maximum densities, grown out. I really appreciate that.

Below is the PDF I have been reading. I have tons of others I printed here, but this is the one I go by more than the others.

Small Scale Aquaponic Food Production (Saved on my Dropbox account.)

Densities shown in it are as follows:

The FAO puts out some really good documents and their numbers are reasonable for aquaponics. Nothing about this is written in stone regarding their estimates of the ones on BYAP. I should point out that according to the same document it is possible to raise 150Kg of catfish in 1 cubic meter of water using other methods (330 lbs in roughly 203 gallons of water)(they also state that these numbers are not appropriate for the methods used in their document). I have a couple of points to make based on that - first is that there is considerable leeway for interpreting the numbers depending on how your system is setup and second, it doesn't appear to be a limitation based on crowding. That's why I made the statement below regarding the higher fish densities mentioned in my earlier post.

Thanks again, mate. I will make sure I keep those two (very important) points in mind, especially while running an aquaponics system in a country where electricity is not reliable.

I think I detect a hint (or maybe it's more than that) of sarcasm?

Not at all. I will be running my AP off solar, though. I will buy a Honda EU-20i gen-set, as well.

Hi guys, thank you for all the help , and sorry just got back from vacation and still have to read through all the posts. I did visit a fish farm and they told me 1 Lb of fish to 3 gallons of water. How ever they had constant spring water and a flow through system. My goal is to heavily stock my tanks because i would like to grow tomatoes (LOTS) and i hear they need lots of nutrients.
DTA

[quote="scotty435"]These figures are referring to your ending weights at the time of harvest

I there any way to calculate the beginning product? (most likely a stupid question) But how do you all do so.

The only stupid question is the one you don't ask!

Generally, you divide the final weight of fish you're aiming for (the maximum load you plan to put on your system) by the size your fish will get to. For example, if you're running silver perch, they're usually considered 'plate size' at 500 grams (just over 1 pound). If the maximum load you're planning for your system is 20 kilos (44 pounds) then you can have 40 fish.

Thanks ! Thats very helpful