Backyard Aquaponics
A place to discuss aquaponics

the spangles and rainbows don't seem to eat it. The rainbows eat the duckweed, but there are so few fish that it takes them a while.

First thing is to understand what your particular fish require. In my case, sub-adult and adult tilapia are pretty much herbivores, but the fry/fingerlings are more omnivores. So I will be starting out with a modest-protein-level commercial flake. I am going to try to make duckweed (ideal tilapia food from what I read) available as I can grow it, and sprouted seeds like oat, wheat or millet once I think they are big enough to handle it. Trimmings from the garden will be tried once we are in to dirt-garden season. I expect to rely on commercial food to some level, just because I'm too lazy to hand prepare all of the fishie meals as well as the family's. That said, I think by offering a variety of natural/homegrown foodsources, the potential deficiencies in one source would be overcome by the strengths in another.

I have researched a lot of text's and DPI documents to formulate this recipe, however, I have written down these ingredients and ratios as a guide only. If you have a better understanding of what to feed your fish or more nutritional info, I'm all ears, but in this case I guess it's trial and error without an R&D team of scientists.
I think it's important to dry out all of your ingredients and grind them into powder the simple reason is once they are bound together they are hard to separate. Making feed from wet ingredients are hard to dry out with consistency when they're combined. Australias major fish feed manufacturer combines dry powdered ingredients and fillers with water (of all things) and air blown ovens to make their product. Being an ex employee I'm reluctant to mention their name and/or any specific processes they use. I will say that unless you buy a pallet of their product it's hard to get anywhere, now you should know whom I'm talking about. I signed a confidentiality agreement before I started their which would allow them to take the shirt off my back if I say too much. I plan on using these recipes to feed barra, perch and crays. I'm going to dedicate tanks and crops to growing stock for these recipes and reducing my overall costs.

Carnivorous = 6:1:3 meat to vege to filler (low fibre, high protein)
Omnivorous = 4:3:3 meat to vege to filler (nice balance)
Herbivorous = 0:6:4 meat to vege to filler (high fibre, low protein)
Young fish = 8:1:1 meat to vege to filler (ultra high protein)

Vege powder (dehydrated and ground into powder)
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Examples: spinach, zucchini, chickpeas, green peas, etc.

Fish powder (dehydrated and ground into powder)
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Examples: brine shrimp, cray heads/shells, guppies, fish heads/bones, etc.

Insect powder (dehydrated and ground into powder)
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Examples: Mealworms, flys, cockroaches, beetles, mosquito & larvae, etc.

All of these examples are quite easy and inexpensive to breed/grow

Fillers
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Examples: wheat meal, brown rice (ground and boiled), soybean meal, etc.

Using the ratios as a guide blend the powders you have made together Combined with raw egg till the mix resembles bread dough. (So it doesn't stick to your hands/spoon)
Flatten the mix out on a baking tray 5mm thick place in oven on the lowest possible setting (less than or exactly 100 degrees C). Bake until the mix is hard enough that you can't make a dent with your finger. Take out of oven and allow to cool. Cut into squares 10mm-20mm sq. place your squares into a freezer bag/container and store in freezer. I would advise the entire mix be frozen, allowing moisture from the air to return to the pellets as it's thawing out. This will make it easier for the fish to nibble on.

Live food
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Earthworms
Flour 75%, fish food flakes (high in vitamins and minerals) 20%, yeast 5%(don't make tequila)

Take your worms out of the ground and place them in a mixture of flour, fish food and a small amount of yeast mixed in together give the worms a day or two so they can fill themselves up with the mixture and excrete the matter they were eating when you pulled them out of the ground. This will reduce the chance of bad things being fed to your fish. Earthworms will eat anything and sometimes it may be harmful to your fish, although I have no hard evidence to prove it, it's merely an assumption.

If anyone tries this approach I'd like to know personally how it went and how the fish responded to it, please pm me with details.