Backyard Aquaponics
A place to discuss aquaponics

Dear all, I am new to the message board but would like to introduce myself and ask a question from you all:

My name is Michael Amadori, I am a graduate student at the State University of NY- Environmental Science and Forestry (SUNY-ESF), located in Syracuse, NY. For a thesis project I will be constructing an aquaponic system with two main goals:
1) Can I feed Tilapia food waste from the cafeteria and get the same growth rates as commercial fish feed. The feed for the fish contributes over 50% of operating costs!
2) What are the nutrient removal capabilities of two different plant growing systems. One will be duckweed growing in open water the other will be lettuce in a pea gravel flood and drain system.

The system will be set up like this:
I will have two side-by-side systems one for food waste and another for commercial. Each system will have three barrels filled with approx 45 gallons (170 liters) and 15 fish each. The water from all three barrels will be fed via gravity to another barrel where a pump and heater will be located. The water (and solids) will then be pumped into a top 25-gallon tank where duckweed will be growing. The water (and any solids) will be constantly flowing out of the bottom of the duckweed tank and into a 50-gallon gravel bed. Once the water reaches the top of the gravel, a suction will activate and drain the water back into the fish tanks.

I just wanted to ask if anyone has any experience feeding their fish with human food (bread, vegetables, fruits, meat, etc..). Any thoughts, idea, or criticisms you have are welcomed. Thanks and I look forward to being apart of this community.

Welcome Michael!

Instead of trying to feed them scraps directly, how about feeding the scraps to black soldier fly larvae then feeding the larvae to the fish?

(I wanted to use scraps from the local elementary school like this once)

I would expect the duckweed - rather than filtering your system - it doesn't like moving water, let it grow and use it as fish food.

IMO, if you are going to research into feeds, to make sure that you start at the same point, you will need to ensure that your systems are both properly cycled before you start. And also probably want to confirm that your stocking levels are within the recommendation, just from reading I am not sure you have enough filtration. In fact, since you are comparing feeds, it is probably best to keep your stocking levels low.

Do make sure that you have learnt and established your system first before doing your research otherwise I believe you might not getting inconclusive results.

Hi Michael
IM doing a similar course to you - enviro management and marine science. interesting to hear that you are doing a thesis in AP

I am +1 for getting both of your systems up and cycled and settled before you starts feed comparisons. even if you do this with som goldies or feeder fish, then replace them with your tilapia, it will give you a solid baseline and remove any variables associated with a new system. that way there will be none of this

are you going to look at the sustainability aspect - constructing from recycled materials, metering water and electricity usage, and looking at inputs vs outputs??

IMO your human waste will need to be high protein to ensure that your growth rates are similar, so it may be worth looking at starting a wormfarm or fly larvae farm to then feed your fish. I am currently looking at the size of a worm farm to feed 25 barramundi, for summer here. . . . its big.

good luck with the research, hopefully we will all benifit from your research

Thanks for your suggestions guys! I really appreciate it. I never really looked into BSF, but after looking around these boards it seems everyone around here is big on them. I will not be setting up such a system now though, I have neither the time nor resources. However, I do have a vermicompost system on campus where I feed the worms leftover food as well. But I would need a very large number of either worms or BSF to use as a feed stock. (as freoboy mentioned) The vermicompost soil will be spread on top of the gravel beds. The soil is rich in many micronutrients that the fish would benefit from.

Leftover food has been shown to be an acceptable feed stock see here (http://ipac.kacst.edu.sa/eDoc/eBook/1400.pdf) . However, they did not raise the fish from fingerling to market size and used mainly bread and fish waste. Not the diverse range of food I will be getting from the cafeteria. I will be blending it, then putting in a meat grinder, making pellets, then drying them to use as fish food.

I am also using this website (http://nutritiondata.self.com/) to look at a complete nutritional breakdown of may different types of food. I will match that to known needs of Tilapia fish.

However, maybe the fish love carrots but hate tomatoes. Or will eat beef but not chicken. Thats what I have been looking for, there is no real info on that.

Also, I did plan on running the system for a while with just gold fish in there and feeding them, I might even add some artificial ammonia just to get a high population of bacteria needed for nitrification.

About duckweed, How still does the water have to be? The surface water will not be "running" maybe just a little choppy.

I will keep everyone posted on the results! Thanks

Welcome, Michael.

It might be interesting to get a representative sample of food scrap, grind it up, and make pellets.

Consider that the fish will not eat some things (if not in pellets). Solid waste collection>worm bins might be an options.

Protein concentration is very important. Test pellets or a representative sample?

Too fun!