Backyard Aquaponics
A place to discuss aquaponics

Hi, I'm new here and this is my first post. Hopefully I'll have a system set-up very soon. In 2-3 weeks!

There is one thing about aquaponics that's keeping me guarded. I have heard that AP is a system where essentially you buy fish food and you end up with fish as well as an assortment of fruits/veg to eat.

That's all good.... but is there a way of feeding the fish at ZERO cost.

I know that there are many discussions regarding this. Yet, I have not found a discussion which deals with this issue as a serious and "whole" subject. Usually there is talk of bugs, maggots, larvae and some people who come along and say that feeding your fish ONLY the above is not enough.

So what I'm asking is an answer to the following question.


Can I LITERALLY produce ALL my fish food on my land and buy NOTHING at all?

I have heard of 5-6 different types of fish feed being grown. Like Duck wheat, larvae, flies, maggots, worms etc.

What do you guys think the breakdown should be?

For example... carnivarous fish... (i know each fish has different needs)

30% Worms, 10% Maggots, 50% Duck wheat 10% Flies. (This is just an example, in reality I have no idea what to feed fish )

Knowing the above information, we can start to produce our own systems which are trully self sustaining. Right now I believe AP is juat a way of turning expensive fish food into fish and fruit and veg. SURLEY this is a huge improvement in efficiency and sustainability but why buy the fish food when there are ways to feed the fish at no cost....

Once I have this information I'll gather it, clean in up and make a tutorial called "How to feed your fish at zero cost".

Thanks!!!

Welcome... short answer Andy... no....

There are a lot of different ways to supplement the feed of any fish... some more than others....

But even in combination... the supplement feeds aren't a complete feed.....

Some might enable fish to grow.... but not optimally...

And ultimately... probably cost, literally, and in terms of labour... as much, or more, than a quality commercial feed...

Hi Rupert and thank you!!!

I have heard that some people (on this site) have cut down their commercial fish feed requirements by half in a number of ways. E.g. growing some worms and catching a number of flies.

You call fish food which is grown a "supplement" so to which extent do you believe these supplements could replace commercial fish food?

Can they replace 50% as some have said? Is there a rule of thumb here? If I can catch all the flies I want, grow all the worms I want, grow as much duck wheat as I want.... How much of the commercial fish food can I replace?

Sorry for pressing this issue still but I believe that there isn't enough information regarding this subject. And I have a sneaking feeling that since fish don't get fed commercial fish food in their natural habitats there MUST be an all natural free solution to buying fish food.

I wouldnt give a straight out no. Its a yes/no in my view. Yes you can feed your fish with a variety of things at a minimal cost (to the pocket) and grow them out to eat them. There is no problem with that. Mind you it will be slow growth but yes it can be done. But also no... as Rupe mentioned it will cost you time... time not many of us have. Another downfall is plant growth. Quality aquaculture feed is formulated with all the goodness and micro-nutrients needed for optimal fish and plant growth. Remember AP is about both fish and plants.

Id suggest to just do it and then report back your findings as Im sure many here would find great interest in it. Unfortunately I personnally dont have the time to mess around or experiment with other food options. Aquaculture feed is pretty dam cheap compared to buying fish and veg from the local stores in my area... and my home grown stuff is a hell of a lot fresher!

Hi Charlie, Can you be a bit more specific regarding this. Like I said in my opening post I would like to make a guide for myself and for others as I TRULY believe that the only input into a system like this should be the rays of the sun. I know it's a bit of a stretch to some people but we have to find a way to replicate nature.




This again just doesn't sit well with me. I have to admit I do not have the knowledge or the experience you guys have (since i haven't even completed my own Aquaponics system yet). But nature is perfect and it doesn't need inputs by man!! It sustains its self and it thrives. Of course natural environments are closed circuits and aquaponics is not since we remove nutrients from the system.

It depends somewhat on what fish species you are growing....

For instance Tilapia and Carp... can be almost vegetarian in diet.... but usually need large amounts of feed for corresponding growth....


I'm sure that someone has actually quantified it.... somewhere....

But there was a "fad" on replacing commercial feeds with BSF.... which proved to be too high in fat content for growth and health...

Similarly... there are now feed companies, especially in the UK.... that are substituting fish meal with meal worms.. as the basis of feed.... with some success....

But that's similarly a commercially developed "complete" pellet feed... with minerals etc....

Growth is inevitably governed by what's known as the "limiting amino acid".. available in any feed....

I any particular feed is low in the required limiting amino acid... then no matter how high any other amiono acid content might be in the feed... it wont be taken up...



True... in a sense.... but they get their protein, fats, amino acids and minerals.... through a range of naturally occuring sources....

i.e... other fish, micro-organisms, plankton, krill, algae, crustaceans, insects etc...

And in natural systems.... their population.. and growth rates... ultimately balances to the feed available...

If you don't want to maximise your fish growth... and/or just have fish as a nutrient source for your veges...

Then, frankly... I think you find the cost of any feeds, and time... probably don't work out any cheaper than just buying hydroponic nutrients... and just doing hydroponics...

No probs, like I mentioed none of this is really new... there are a thousand different things you can feed your fish, some of which you have mentioned. You need to simulate a balanced diet for growth and health as you would with any living creature. This is not new to AP or RAS for that matter and there are many within the forum that formulate their own fish food.

A simple recipe would be something like..
*grounded soy bean
*grounded corn
*whole wheat flour
*garlic powder
*eggs
*dehaydrated milk
*Azomite

Mix ingredience place in oven at 180F for 2-3 hours. The finished product would be similar to a crumble.

-or-

*ground whole wheat
*sprouted wheat
*whole chicken eggs with shell and all for calcium
*sea salt for trace elements

-or-

*10 3cm shriimp (cut off the hard head shell section and tail)
*couple of small fish (3cm - whole)
*a few leaves of lettuce and spinach
*handful of peas
*sheet of sushi seaweed
*omega supplement capusle that contains some vits & minerals.
*couple of cloves of garlic

-or-

*Combine 0.5 pounds (about 250 grams) of whole uncooked shrimp (or equivalent), including head/shell/tail, with the same weight of frozen peas (slightly defrosted). Grind into a very fine paste.
*Stir in about 1/2 teaspoon (0.5 mL) of Spirulina (algae) powder. If you wish (and I never have), also stir in about 3-mL of liquid vitamins. I add FAR more Spirulina powder than is recommended in this recipe.
*Set mix aside.
*Sprinkle 4 tablespoons (15 mL?) of Agar Agar flakes over 2.5 cups water. Bring to boil, then reduce heat and simmer for 5-10 minutes. Please stir frequently until competely dissolved.
*Pour dissolved Agar solution into bowl of shrimp/pea mixture and blend thoroughly.
*We always skip this step, but it is in the recipe: Pour into covered casserole dish and refrigerate overnight.
*Place the contents into baggies, layering them flatly. Put in freezer.

As mentioned these things take time and the reality is that for most of us its easier to go grab a 20kg bag of feed. All these above still miss other macro nutrients, amino acids and minerals etc


Obvious others are duck weed, roaches, crickets, maggots, BSFL, azola, leucaena meal, meal worms, worms etc etc etc....





Your right... nature doesnt need input by man because it is a living eco system with inputs and outputs and evrything in between. We are creating a closed loop artificial system and its difficult to provide all the goodies and nutrients required for maximum, healthy plant and fish growth without the assistance of specially formulated feed. Even then most of us need to add potassium and iron etc in some form. PH plays a big part in nutrient uptake so this also is something that nature doesnt need to worry about.

Charlie and Rupert

You both amaze me with the depth of your knowledge.

I am learning so much, i started this thread with the idea that you could COMPLETLEY replace commercial feed with home grown solutions and only a few posts later I'm already convinced that commercial feed has a role to play.

So a new question.

Since we will always need commercial fish food what should a person do if they have access to an endless source of free or home grown alternative.

As an example, I plan to start my AP system in an agricultural/rural area where I can set up traps and catch possibly millions of flies/moths and other insects. One summer I lit a few candles outside to create a nice atosphere and the amount of moths which it attracted almost caused a fire. They where everywhere!!

I also have access to chicken and quail bird poop.

So seeing my "strong points" here, I would say that it would be quite easy for me to give my fish worms and insects considering that they are abundant in my location.

I can understand what your saying, that it's offen not worth the time/effort to make my own fish food. I still want to point out that It's a shame (and kind of wasteful) to ignore the abundance of fish food alternatives that exist in my own back yard.

Nature adapts and finds an equalibrium so why not adapt my AP system to incorporate a free and abundant raw material to substitute some of the commercial fish food I will soon be buying?

Why not indeed... supplementation is fine...

Don't forget duckweed... and many fish will also eat lettuce and Silver Beet/Spinach leaves.... and then there's the leaves from the Moringa tree... (do a search )

Then there's also pest control.... like feeding the bloody caterpillars that want to eat your veges... to the fish...

I'd leave warm blooded animal manures out of the fish tank though... (search again )... and just use them in your compost/worm bin/wicking bed....

Your subject for this thread is
"Feeding fish at minimal cost."
This is different than "Feeding fish without any off farm inputs"

If you want a system that uses nothing but nature. Get a property with a big farm pond, stock it with some fish and let them grow naturally with just a little extra management and use some of the water to grow a veggie patch next to the pond. This will cost you more space and time and you will be limited by the natural conditions of your pond and the space around it.

If you want to raise fish in recirculating tank culture (which is what most aquaponics is) you need to provide the fish with complete feed for them to grow well and also provide your veggies with good nutrition and in general you also need to add some form of power to move water and keep it aerated since it is normally a system stocked far beyond what nature can keep aerated and circulated with just gentle breezes.

In tank culture people have studied Tilapia to figure out that they can replace up to 50% of the commercial feed with duckweed before they start seeing a loss of growth. That is the only study I know of that seems to have much bearing on the question you seem to be asking.

Most other studies I know of have more to do with replacing ingredients in pellet feed which would still involve buying the commercial feed (or all the equipment and other ingredients to make your own pellet feed which would probably cost far more long term and is rarely cost effective to start up unless you are selling thousands of pounds of feed per month.)

If you really want to do the research and start trials of growing your own fish feed on farm I applaud you and I would be interested to learn about your results. However, I don't really expect that if you put decades into re-inventing fish food and are successful that you are likely to just give the answers away (which might be why you are not finding an easy post somewhere on the forum with the results from some one else who has been successful at it.) I expect it will take acres to grow/catch all your own fish feed inputs and the activities of collecting/growing/formulating and making your own fish feed could probably be a job in and of itself.

So when you speak of feeding fish at minimal cost, does time, land and electricity figure into the cost?

Truth is most of us don't have the answer you are looking for (it is not like we are hiding it as some special aquaponics secret.) If we knew how to feed our fish at minimal cost we would all be doing it. So far people have found that the best balance between time, cost, effort and space for most types of fish seems to be commercial pellets that are formulated to grow fish out.

If you are willing to substitute your time/space/ and money to buy equipment to grow/make your own feed then you might avoid bringing in outside commercial fish feed but I don't see that as minimal cost.
If you are willing to sacrifice space, fish and plant growth you might manage to grow some fish and veggies on natural feeds in a farm pond but you will use up more space and not get as much per unit of space.
If you want to do this in a small recirculating aquaponics system you will still need some way to power water and air flow and you will need to devote a huge amount of time and space in comparison to growing your feed stuffs and you likely will still only be able to manage a small amount of fish and plants on your home grown feed inputs.

It is all about choices, what are your primary goals with aquaponics and how does it fit into your space and life.
I would recommend starting with a basic system and feeding the fish a commercial fish feed so you can get started with learning while you research further into other options.

An abundant sources of good fish feed supplement is not to be scoffed at. I hang bug lights over tanks (just beware beetle carapace that can clog filter screens and distrobution grids.)

I would avoid the bird poo in aquaponics (warm blooded animal manure is not welcome in my salad bowl.) Bird manure should be composted before use in any garden that people might be eating raw salad out of. Spread the bird manure in fields where the crop won't be harvested for 4 months or compost it before use in the garden. That said, I have a duck-a-ponics system that I grow bananas and fodder for the birds in.

Read a bit about permaculture and how to make use of all the wonderful resources your property has to offer, Aquaponics is only one part.

Thanks TCLynx

TCLynx, thank for your reply. It has given me so much understanding. The way you say things is clear and to the point, without getting away from the subject.

I have written some replies to your post with red font, inside your quote below.

I personally think you should always have some regular commercial feed and supplement and vary with some diverse and natural diet when you can, consider them like some "treats" for the fish in the form of all of the above (duckweed, bsf, worms.....)

Also, adding to the examples above, many fish are predators/carnivores/omnivores so also having some small fish (mosquito fish, guppies - there's a thread about the subject here : viewtopic.php?f=2&t=13601) which breed prolifically could be helpful. The same goes with tadpoles.

Agreed... but most fish don't live on a vegetarian diet...


It can... but the cost of installing enough panels/batteries to capture/store enough energy.. to keep your system.. and particularly your fish alive... during cloudy/rainy days.... is still hugely expensive...


It might be more... the answer you wanted to hear.....

As I said before Tilapia.. and some other species can be very vegetarian in diet... and duckweed is generally a supplementary feed for many species...

The bottom line is.. other than a few species, like Tilapia.... growth rates can't be sustained by substitute feeds...

And the amount of tank space, and time.. required to produce enough duckweed to supply the fish diet... probably would be better dedicated to another fish tank... fed by a commercial feed... grown & sold...

You're correct that it's becoming almost impossible to find a feed that's not GMO based in terms of the grain meal ingredients...


Please do.. I admire your philosphy and commitment.... please post all data results..


It may well be.. that it is....

What are your actual goals in setting up an aquaponics system??


And by all means use them.... but your fish require a balanced feed.. to grow properly... and do so healthily...

I'm not knocking you Anthony... I'm just not sure what your goals really are... in terms of aquaponics...

Commercially... it just wouldn't make any sense...

In a backyard system... with the intent to produce some veges and fish.. for food....

Then by all means... use any supplements.... but fish feeds are just so much quicker, and easier... and they're just not that expensive...

Happen to have a link to that study TC?

You know Dr. Rakocy did a study years back at UVI where they fed a strict duckweed diet to Tilapia over a given period of time and the fish actually lost weight. It took them more energy to consume and process the duckweed then what they actually got from it.

I agree with Rupert on this, for 99.99% it's going to be a no but if you happen to be an aquatic nutritionist you could probably plant a combination of things and then mill your own. Not practical in most situations.

Even then, your starting at ground zero as far as feed rates vs plant area, nutrient deficiencies, and a whole gambit of other situations.