Backyard Aquaponics
A place to discuss aquaponics

Hello there,

I have a small system consisting of a 55 gallon FT, 55gollon ST and 3- 35 gallon grow beds cut lengthwise in half. I am questioning if my 18 finger size goldfish are supplying enough nutrients to my plants since They are slow growing and are somewhat yellow in color.

I have used liquid fish fertilizer (5-1-1) in my soil garden and it has worked very well. What are your opinions for using this in the AP setup? The mixture is 1oz/1gal of water. I was going to just apply a small amount to the base of the plants and observe the results. The current chemistry is PH 7.6, Ammonia 0.00, Nitrite 0.00, Nitrate 0.00. I plan on resampling the chemistry after the dosing as the fish fertilizer has a strong ammonia odor and I don't want to harm my fish.

Any thoughts?

It is quite normal to supplement BUT you need to be aware of what you put in and why.

First step = test your water - always need to get a handle on ammonia, nitrites and nitrates.
You have done that so good - your numbers show a lack of nitrates.

[edit] didnt this option work for you ? viewtopic.php?f=1&t=26631&p=532081#p532081
The advice below is pretty much the same anyway.


[edit] be careful with Liquid fish. Safer to stay with the seaweed extracts or go with the blood&bone #3 below
have read of this - viewtopic.php?f=3&t=13488&p=346303&hilit=maxicrop#p346303


You need to have on hand two types of fertiliser
#1 is the basic seaweed extract, this has trace elements and potassium (and sometimes iron)
but is very low in nitrogen and has no phosphorous.
This is basically the Seasol that people mention (an Australia Brand).
see here for maxicrop equiv and mainly note comments by Scotty435.
viewtopic.php?f=11&t=26889&hilit=maxicrop

#2 *IF/when* your system is low in nitrates *then* (and only then) should you look at a nitrogen input.
In that case the best options are the seaweed extract with additional nitrogen
(often as urea which goes to ammonia first)
It is better not to get a fertilizer with excessive nitrogen and avoid one with phosphorous.
Organic is better as mineral fertilisers can mess around with pH and other chemistry.

You need to add these if your system is low in ammonia and nitrates mainly for the plants.
Your fish will do the role of keeping the bacteria fed.

Personally I prefer to add direct to grow beds with a watering can.
You can use a half strength watering can dose and your fish tank/system volume etc is irrelevant.
I prefer not to add anything to the fish tank.


Then couple other options...

#3 in a young system without much solids you can add blood&bone powder to the grow bed.
It will provide something for the pants and tend to stay around the roots where it is accessible.
Scotty435 will know one to use - I think he mentioned one available in USA few posts ago.

#4 other option is to foliar feed your plants. Particularly once your nitrates are up this is a common way to get minerals and trace elements to your plants without affecting water chemistry too much. In this case you can pretty much use anything suited to foliar application.

with all supplements don't go overboard. Small amounts and once week etc (not often).
Adding excessive amounts of fertilisers etc causes problems - not solve them.


hard for us because here in Australia we have three products that work very well (Seasol, Seaso Power feed and Blood&Bone plus potash) but not available in US and products in USA are not quite same.

Hi,

Thanks for the information.

I went ahead and dosed with a small amount of the liquid fish fertilizer at the base of the plants. The dilution was 1oz/1gal and I applied about 4oz of the mixture to the base of each plant. The water chemistry was about the same, the only exception was a very slight increase in the Ammonia reading. It rose from 0 ppm to a little over 0.25 ppm. There seems to be no change in the fish activity.

Speaking of which, in re-reading some of your earlier inputs, I will change the food for the goldfish from flakes to a higher quality sinking pellet as well as adding some water plants. Also trying to find a source for bone and blood meal as per Scotty435 suggested. So far now luck yet.

Thank you.

the big problem with the fish emulsion/fertiliser is it moves your nutrients quite a bit (as you note).
OK while you don't have any but bit of problem for ongoing use as you get a fairly quick nutrient response and bioload.

that's where the seaweed extracts with added nitrogen work a bit better.
the Blood&Bone works OK because it tends to stay in the grow beds and is a slower release.

adding to the GB is a good idea, it helps.
If you use any more best to keep it pretty diluted and at base plants as you did.

it is definitely good stuff in the soil garden and wicking beds.