Backyard Aquaponics
A place to discuss aquaponics

Soooo been doing a bit of reading(can you tell what i do with my spare time?) and have discovered that Tilapia love to eat algae and duckweed(and some other water plants) soo this gets me to thinking. Why not just grow a crapload of this stuff in their tank for them to eat? some science dudes fed them only duckweed and the likes and said they ended up healthier than the ones they were feeding pellets?
:Some thoughts and questions:
1.It's my understanding that duckweed and the likes also eat algae...if this is true that might bugger me right from the get go.
2. no one has mentioned doing this in their ap system i'm guessing there is a reason?
3. would it take an unholy truckload of the stuff in a tank/pond to keep them fed? anyone know how much the average fishy eats of this stuff in a given day?
4. would having these plants in the tank eat all the fishy poop and kill off all my grow bed plants?

I hear they munch veggies but would they nibble on some aquatic worms if they were squirming about down there?

thoughts like this are why i'll never be president
"it's 3 am... a phone is ringing in the white house but president cactus is in the other room trying to feed fish from thin air"

5 a.m. research ramblings and findings

"another amazing feature of these plants is that they can double their mass in less than two days"

"In a properly designed water recirculation and purification system, duckweed can remove as much as 99% of the nutrients and dissolved solids in wastewater." friggen ecosystem

"The optimal standing crop density of duckweed is between 400 to 800 grams per square meter" somehow important to all this

"Duckweed protein has high concentrations of the essential amino acids lysine and methionine and is also high in trace minerals and pigments."

*Edit-nixed ramblings*

Looming.... there's constant reference in almost ALL Tilapia reference material and within the threads of everyone here running Tilapia ... as to the fact that they'll willingly eat duckweed and algae, especially off the tank walls....

Indeed it's one of the major attractions of stocking Tilapia.... they're primarily vegetarian in their diet.....self breeding and self feeding...

Most people probably grow their duckweed in a seperate tank.... or float it in a container on top of their fish tank....

There's some major threads concerning duckweed on the forum.... try the new improved "search" function

can never get the search to work no matter what i enter it comes back with zero results. i'll continue to update my original post as i find random info then save it all to a word file and zap this post sorry :/

*edit* searched duckweed 3 other post came up none of which were talking about using it as the only food source. might leave thread if i can figure this out properly...Corse my search might still be bugging out but 5 is better than the usual 0 i get when searching ^_^...OMG wait so you're saying pretty much everyone here but me knows they will happily eat nothing but this stuff and be just fine?!?1 WOOOT i LOVE this stuff it gets better and better!!!!

Also sorry to all if i'm a bit dense 6 a.m. after working for 11 hours will do that to ya xD viva la fishy!

At one point I was raising duckweed in a "Duckweed Detour" in my system. The plumbing was a bit messy and I got rid of it during a re-model. It was too small to really raise the amount of duckweed that my tilapia wanted.

Duckweed is a wonderful food for tilapia, and they love to scrape algae off the tank walls, too. In my breeder aquariums, you can see all the little teeth-scrapes in the algae. When my fry get a little larger, they will make the tank walls spotless in their quest for snacks.

Leafy trimmings from the garden, spinach and water hyacinth have all been appreciated by my tilapia. The only thing you have to watch out for is that plant fibers will wrap themselves around the pump impeller. That's why I really liked the duckweed, of course. No long fibers.

Sorry Looming... looks like some of the older threads haven't been archived back as yet... or search indexed....

There is an entire thread somewhere.... someone will find it for you

I agree, fibrous things are bad for pumps

My fish ate the duckweed faster than it could grow so I would imagine a vary large shallow tank would be needed. I would like to know how many square feet or meters of duckweed would feed 1 tilapia. As to algae, my fish eat it faster than it can grow too. However if you were to make a algae tank part of your system I would suggest putting air stones in it and some how disconnect it from the system at night because it can use up all the oxygen in a system over night a really throw the pH out a well. Then on the next new day, dump the water in the algae tank and reconnect to the system (to get rid of water with wrong pH). Also, keep the fish tank shaded so it never really gets growing well in the fish tank it self.

my final thought was to rig a crawdad/crayfish/*insert yummy critter* tank to reuse my fish scraps as food for the shellfish and grow duck weed on top of it. should take care of itself nicely perhaps :

I did a search and came up with the following four threads that seem to have quite a bit about duckweed and tilapia...

viewtopic.php?f=26&t=1110

viewtopic.php?f=3&t=33

viewtopic.php?f=26&t=954

viewtopic.php?f=3&t=100

Now this topic I can definately help with ,, I have a farm in Thailand that i set up and my brother-in-law runs for me. Last season we collected just under 10,000 kg of Tilapia.
Don't think I'm a rich euntrepenuer , LOL , we actually made a small loss:(

Ok , yes Tilapia are extremely good at filtering algie from the water , they have special gill rakes to do this. Poorer farmers often just use the "green water" method ,, no feed pellets, they usually hang bags of fertiliser in the water and get an algal bloom going.
Using the green water methos Tilapia take some 18 months to get to preferred market size. On good pellets they take 5 months!

As for duck-weed ,, yep Tilapia love it and yes it has good protein , when reading about it make sure whether the quoted protein levels are for dry weight or wet ,, BIG difference here as duck-weed is mostly water. As with a lot of things it isn't as easy or economical as some information leads you to believe. To grow enough duck-weed to supply the ideal protein amounts takes a HUGE area , remember calculate your needs using dry weight protein levels then times that amount by 10 or more to get your actual weight needs.
Also , duckweed has tremendous growth rates at certain temperatures ,, once your outside of that temp range it slows considerably.

A fun addition to your backyard system ,, yes for sure . An economical and practicle solution for feed ,, no it's not.

Cheers.

Since duckweed only needs a shallow water volume I wondered whether you could stack up trays to grow more in a vertical space. Hop into the wayback machine:

viewtopic.php?f=1&t=239

Sounds good,duckweed needs a fair bit of light but happy not in full sun,so stacking could be a ok for a backyard system.

I would get a decent size shallow container to grow your duckweed and azolla (look that one up) in. Once it completely spreads out harvest 90% of it and dry it out in the sun... Just keep doing this. Soon you will have bags and bags of dried duckweed that you can grab a handful anytime to compliment your regular feeding.

I have looked at feeding them on only duckweed before, but unless you had the space you couldn't do it.
My plan is to grow zuchinis, cucumbers to feed the tilapia. Use some pellets and dried duckweed. And any leafy
matter which are kitchen scraps I could blend up with some carrots and spirulina to make a frozen food.

I would think it is very possible to feed your tilapia with only the products of your AP system. But because
it isn't a perfectly closed loop you will still have to add outside foods like pellets. Or from duckweed ponds.

(Engineering hat on)

How about having two shallow duckweed ponds, each with a slope from very shallow to deeper water. Connect them using a tidal arrangement that has been bandied about before. To harvest the 'weed, pump water from the one to the other. When the one tank goes low the duckweed would dry out on a screen that is situated below the high water line and above the low water line. Maybe the screen could be removable to bang it into a bucket or something.

Forgot to mention this. If you feed worms to tilapia do not over do it. The fat content of worms can cause liver problems in tilapia that can lead to death. I plan on using BSF larva(with the fat removed from blending and boiling) along with duck weed, algae(sprillia), and other veggies. I want to add protein to their diet so they will grow out in 12 months max. Well, thats the plan any way. Time will tell how it really works and how well I will be able to dry out worm mush into flakes.