Backyard Aquaponics
A place to discuss aquaponics

If I were to ignore the biosecurity risks and I was growing a carnivorous species, would there be anything wrong with feeding my fish wild caught gambesa? As a primary or possibly entire feed ration?
I realise that it risks disease and pathogens, but I'm only having a brain fart here and besides I'd happily eat fish from the waters the gambesia would come out of.
Had a good decade and a half with wild capture fish in aquariums, adding new specimens from various places on a regular basis. The only things I introduced accidentally were some mussels attached to the new fish. Never had a drama with it then.

Thinking more, this would only be possible in a very small system with display/aquarium fish.
The number of gambesia required to 'grow out' fish would be enormous...
A small system though, I reckon I'd give it a go. Even if that meant freezing the gambesia first to try to kill parasites.

If you had an efficient way of trapping them

Stuart made some good points here. Thank you so much. All points noted. On Antarctica, we shall discuss later.

Sharing with you a smallholder farm system in Bangladesh and a quote. Source online FAO.

Pond culture or I would like to look at it as an integrated AP farming system has a number of advantages, in terms of inherent production efficiency, over crop production and livestock rearing. The three dimensional aspect of a pond habitat offers a variety of ecological niches which can support numerous and diverse organisms.

Also sharing a few things that I have so far adopted as part of the Goal #1 of AP research on feeding fish naturally and to have a low marine footprint in our AP system.

1. Grow Water Hyacinth in the fish tank for water quality management, keeping it in good control by feeding shredded leaves of about 20 to 30 plants to fish and rabbits on alternate days as part of their feed regimen.
2. Using the rabbit manure about twice a week 5 kg each to manure the pond. So that is the give and take.
3. Grow Azolla as a supplemental feed, separately in a grow bed, feed fish about 1 kg raw added to the tank directly and 1/2 kg dried in sachet along with rice bran, again based on feed regimen composition and will be increased periodically depending on the average bw of fish. Chicken love this too.
4. Usage of locally available rice-bran and oil-cakes as feed supplement.
5. Usage of Indian almond tree leaves for natural disinfection.
6. Usage of Moringa leaves for nutrient supplementation. Azolla and water hyacinth also helps in providing all those scarce plant nutrients.
7. Sludge from waste solids removal is being used for other garden plants and trees.
8. Recently added a few snakehead fish (Kannan SP) to control huge Tilapia recruitment. It is working.
9. Usage of banana. I put the first 5 banana skins into the filter tank today. Thanks to Jay's quick answer.

It is sad there aren't many AP examples to show case similar efforts and help. I do not know if it is worth pursuing as part of a commercial AP program or should I lay aside this futile pursuit?

No warm blooded animal's manure should be introduced into an AP system. The last thing you need is someone dying because they got a deadly illness from your produce. There are some backyard systems that use manure in their AP systems, but those owners are crazy. I would never risk my family with that kind of dangerous behavior. There is a place for manure in traditional soil based agriculture. That is AFTER it has been composted. A safe way to close the nutrient loop would be to include soil based agriculture to grow feed. That food can benefit from composted manure. There are some people that feed manure to black soldier fly larvae. Their stomachs are supposedly capable of killing any pathogen. I am not sure if I would go that route though. Still too risky for me.

While I agree with what Ron says above... especially with regard to e-coli and/or salmonella..

It is quite common practice in Asian countries to place rabbit/chicken cages above ponds full of Tilapia.. or rice paddies with Tilapia.. especially in Thailand...

But then I've seen Tilapia grown in cess pools... literally... in Vietnam... and exported.. to Western markets...

There are other ways to encourage phyto/zoo plankton.. and algae growth in pond based aquaculture...

Ron, thank you for your comment. I wonder why would the UN agency FAO promote such practices for global use. Here is a document from my archive for your quick reference - http://www.fao.org/docrep/003/x7156e/x7156e03.htm

Filter tank? I thought you were meant to put it in the growbed for worms to eat
Manure - you crazy? grow a dirt garden instead.

So we now have a flow of people not knowing or understanding a practice or technology but going in the other direction this time.

As Rupe said it is a widely practiced method of growing animals and often the same water is used to irrigate crops. Since people have been doing it for centuries without massive or even minor regular outbreaks of salmonella, E. coli or the like we can probably conclude it is pretty safe.

I was talking with a poultry consultant a few months ago who had done a bunch of work helping these traditional systems to incorporate modern methods (not I said incorporate as in include not replace). The main thing he was doing was helping to make the growing areas bio secure because wild fowl were bringing in flu.

He said that the only reason we couldn't use the same techniques in Australia were because of EPA regulations and marketing issues.

One thing about these system is that they are extensive, ie big or rather huge (relative to fish numbers). Such systems need a massive input of energy (from the sun) in order to grow enough food to feed the fish and drive the growth. It may be possible to merge RAS and algae growth into a balanced system but it would be a good idea to understand both methods before you start to try and put them together.

So you can use manure - for what purpose?

In extensive systems the fish get their food from eating phytoplankton (algae) if they are filter feeders or zooplankton if they are not (well filter feeders eat zooplankton as well eg whales). The nutrients added to the pond feed the algae growth and the algae feed the zooplankton. If you take it far enough you get bigger and bigger life forms. In some systems you have feeder fish species that eat the zooplankton and then get eaten by the species that you actually want to harvest. The manure provides the nutrients that feed the algae and drive the growth and production (along with sunlight) of the system.

While these systems work they take a lot of skill to manage. Ideally the water needs to be pea soup green all the time. Which means that managing oxygen can be a problem at night. Maintaining the algae growth is a fine balancing act and not something I'd want to do. Easier with a fish like tilapia but not something I'd want to do.

You can incorporate this style of system into AP but trying to do so in your back yard soon gives you an appreciation of the scale you need.

For example set up a series of tanks (many years ago I used baths) and grow algae and then all sorts of creepy crawlies in each bath. Periodically drain off a portion of the water and catch the fauna in a sieve and feed to your fish. Now imagine a tank full of say mosquito larvae. Even if it is choockers how many grams of food are you going to get per 1000L. I can tell you it is not much from a 200L bath which is why pond need to be so big to support the growth of feed for fish.

The system I had was a series of baths that I would drain from one to the other through a net bucket. When the water got to the bottom bath I pumped it back to the top one. Produced lots of live food but the quantities were tiny relative to the water involved. Since the whole thrust of my commercial aim is to reduce water use it was not an attractive line of inquiry.

Jay, on further reading on the uses of Banana peel, I came to know that Scientists in Brazil have discovered that banana peels can be used to clean polluted drinking water. Banana peels decay and stimulate lots of bacterial growth. Banana peels can be reused up to 11 times for filtering compared to active carbon.
Plus, banana peels contain nitrogen, sulfur, and carboxylic acids. Hmm..those are some things that our plants could use. Here is the link to the scientific paper. http://www.delish.com/food/recalls-revi ... ?GT1=47001

Thanks for confirming that such practice is safe... I always knew it is other direction and I will try to dissuade others to follow suit until I make some decent harvests with this approach and prove it is feasible in a commercial AP sense.

Again, we are talking about extensive, not intensive systems. In Asia, they also use night soil. I do not care how much it is proven in pond culture, I am never going to intentionally introduce warm blooded animal manure into an AP system. Also, the real issue is not the fish, we cook them. It is the vegetables. If we were talking about pure aquaculture, it might be a different story. But we are on the BackYard AquaPonics forum, not an aquaculture forum. I like my salad salmonella free.

The determination of the feasibility... wont be based on a successful harvest... although this might be an achievement in itself...

The real measure would be to determine the growth rate.. FCR... and relative cost of production... compared to a traditional pond based approach...

Given the scale of your plant production... even if your methods prove "feasible" in terms of a fish harvest....

It wouldn't suggest your "project" is commercially viable.. even from an aquaculture perspective.. if you can't out perform pond based aquaculture...

Regardless of whether the incorporation of some plant production means you can define it as "aquaponic"... or not...