Backyard Aquaponics
A place to discuss aquaponics

Will see how your fish take to it Les. Once I get my new system up and going, I am hoping I will have one of my ponds spare for growing duckweed - and azola if the SP and JP like it.

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.

Hi,



Spent grain from the brewing process is good food for lots of animals.....particularly poultry and horses.

In the days when breweries used horses to deliver kegs of beer in the cities, the breweries would feed the horses on the spent barley......the only downside (if you were the wagon driver) was that it induced flatulence in the horses. Flatulent people were said to be "farting like a brewery cart horse."

Whether it would be food for the fish.......I haven't got a clue. Try it!

Duckweed is easy to dry. I did my first batch by accident. I threw some out and when I went I looked at it closed a couple of days later, it was completely dry.

It does require turning but it's very easy to do. I doubt if you need to go to the trouble of using a dehydrator since you can put a a lot of duckweed on a tray.

The trial that a previous post referred to involved something like 800kg which is an enormous heap of duckweed.

Gary

I have a feeling that the spent grain from brewed grains are used for poultry becasue of the high B vitamin content of the yeasts or something like that. Not sure if the fish have a high requirement, but i don't think it would do much harm.

Greenedo/VB, the concept you have for sprouting sounds good. Give it a whirl. In fact, I might try to get some better seed and have a go, too. Great idea!

I built an expiremental pond 7mtr long by 700mm wide for about $23 in brickies plastic sheet and some fencing wire(serious!) just to get a feel for things. Allthis talk about duckweed gets me to thinking the same thing would make a great duckweed factory without a big outlay and if it didnt work big deal. I reakon the crays would love it as there definatly not picky. I had some small lettuce and a type of Thai coriander on rafts and the bastards dragged it all down through the foam and ate it the first night!!! Hmmmm cray tails with lime and coriander butter sounds good.

But seriously what about just buying an old blender throw in your duckweed your spent grain a handfull of worms from the worm farm etc and hit pulse. Then pour into trays like a fruit leather, because youve ruptured the cells it will dry very quickly and it will be in a thicness you regulate and you wont have to turn it. Hell i could give it to the kids for lunches

I just came across this document regarding refinement of copepod nauplii breeding for fish foodsource. I have not heard much of this organism so I don't know how relevant it is to food fish, but the aim is on ornamentals.

Intruiging nonetheless:
I always love it when the word "bio-reactor" is used.
http://www.jyi.org/research/re.php?id=843

What a big read! especially for a sunday.
Quite funny what they are calling a bio-reactor, does this means that the jar with the airstone I have for hatching seamonkeys (can't remember proper name at the minute) is one?
The goldies love them anyway

guys, there is an indepth FAQ on them in the download section!

What foods are we feeding our fish? What do they contain, what ingredients are needed by the fish and which are safe for human consumtion?

Does homemade/homegrown food contain enough vitamins and minerals to support the fish? What is the cost comparison? What is the best way to supplement the vitamins in homemade fish foods? Anybody have any recipe's to share?

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I have a friend who is a butcher who is getting me some beef heart to try this recipe: http://www.calypso.org.uk/Aquarticles/a ... heart.html
I am going to use spirulina wafers instead of the tetra-min I bought only because I am not eating these fish. The wafers contain:

Ingredients (THANKS DANIEL)
Fish Meal, Spirulina, Wheat Flour, Shrimp Meal, Rice Bran, Soy Protein Concentrate, Corn Gluten Meal, Alfalfa Meal, Carotene, Torula Dried Yeast, Fish Oil, Lecithin, Vitamin A Palmitate, DL-Tocopherol Acetate, D-Activated Animal Sterol, Thiamin Mononitrate, Choline Chloride, L-Ascorbyl-2-Polyphosphate, Calcium-d-Pantothenate, Inositol, Niacinamide, Riboflavin Supplement, Pyridoxine Hydrochloride, Folic Acid, Menadione Sodium Bisulfate, Biotin, Vitamin B12 Supplement, Ethoxyquin (as an antioxidant)

Using natural and homegrown ingredients, how do we provide everything the fish requires?

Please post constructive and informative posts...

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.

Tim,

Every small livestock ration I've ever examined in detail seems to contain animal protein (in the form of meatmeal, bonemeal, blood meal, fishmeal), plant protein (in the form of lucerne meal, soybean meal) and some grain products/byproducst (including wheat barley, amaranth, lupins, millet, bran, pollard, etc).

Taking poultry as an example, the ratios of each of the main ingredient groups changes to reflect the specific needs of the type of poultry (layer, broiler) and its age (day-old, weaner, grower). Day old broiler chicks require high protein and low fibre, while adult layers need less protein and more metabolisable energy.

In a homemade context, I suggest that fish are similar.......animal protein (maggots, worms, minced steak), plant protein (duckweed, azolla, silver beet). I admit that I'm not sure what role, if any, grain-based products would have......but an analysis of the dietary needs of fish should answer the question.

There's nothing that says that these things have to be combined in the one meal. As you are aware, fish (and most small livestock) are opportunists.....they'll eat what they can get their mouths around.....so you can feed them one after the other.

Some time back, I proposed a regime where I would feed animal protein first, followed by some sprouted grain or seeds.....and leave them to graze on duckweed.

My reasoning was that uneaten meat and grain will contribute to the pollution of the fish tank (and they are the most expensive ingredients) so I'd want them eaten first. The duckweed floats (and doesn't impact the water quality) so it didn't matter if it didn't get consumed immediately.

Given that fish in the wild often have to do with what they can get, I'd suggest that, if your diet is approximately correct, the only issue you'll encounter is the rate of growth, Commercial diets are formulated to make things happen very quickly.

One more thing......every creature has a requirement for particular amino acids. If they are missing from the diet, you'll experience dramas.

I hope you find this useful.

Gary

Tim,

I've just commenced a maggot-breeding trial based on bread and milk and the eggs have just hatched - see photos in my thread "Gary's System."

Nice information people.

I'm of the 'observe nature and replicate' school of thought.

For some species, this may be impossible, - not covered yet - for others, there are papers analysing gut contents of wild fish in various waterbodies.

What this method doesn't take into account is minerals etc taken into the fish by osmoregulation. For this you'd need a breakdown of the water itself.

General guidelines are however given as to the quality of water required for specific species. Using these and a breakdown of natural diet will see you well on the way to understanding a species dietary requirements.

I don't think beginners should be making their own food, unless guided by more experienced observers, or capable of LOTS of reading and cross referencing. This doesn't mean don't supplement, it means don't try covering total diet with what you've made up till you know what your fish want.

ie: Kokopu (banded) eat anything that moves, and is of edible size. Their natural environment is shallow and slow moving forested streams. These streams are noted for a higher content of invertebrate grinders and less fine particle matter feeders than would be found in a grasslands stream, where photosynthesis produces more algae, and leaf litter is drastically reduced. In conjunction, a large portion of the Kokopu's dietary intake is from terrestrial insects.

I observe the natural habitat, read what I can and 'conjure' the following.

The water these fish seek out (highly migratory) is clean, has abundant insect life outside of the waterbody due to high vegetation, and within due to a constant source of wood and leaf debris. This water is also shaded denoting less algal growth, and less algal grazing insects as a consequence.

The higher content of leaf litter also provides a constantly replenishing source of surface area for younger bio-film to establish. The insects feeding upon this leaf matter ingest the rich nutritional content from the bio-film which is then passed on to the fish.

Water clarity, lack of richness suggests osmoregulation is less important for mineral gathering than in other species that thrive in richer waters.

Shrimp - would you believe they'd rather eat slaters and spiders. tis true. they'll take the shrimp, but not so readily. Shrimp are algae eaters... see the connection with the environment?...
Worms - Like most fish, these make them go crazy suggesting much mineral content in Kokopu's diet is derived from the aquatic worms found in the beds of kokopu habitat. Gut content analysis confirms this.
Koura (kiwi yabbies) Kokopu love these. Also found in the same environment as the kokopu. Opportunistic feeders that eat much of the bio-film enriched leaf matter.
Elmid and riffle beetles - wood grinders - So are slaters! This denotes a need for complex carbohydrates -cellulose and lignin, which is dealt with in a Kokopus stomach by enzymes. They won't eat carbs as such, but get it from the insects they eat.

Anyhoo, I could carry on for a long time on what they eat and what what they eat eats.....

Natural observation requires a lot of just that, observation, but imo will definately help you come to terms with a particular species general requirements.

When trying to provide a more natural, organic diet, this is my approach.

Like feeding eggs, most fish love them, but we all know the difference between eggs from battery farms, and eggs from free range chooks who feed on young weeds and plant growth, seed, and insects.

The difference to us is very clear, and would be to fish as well.

Tim, the recipie I used was http://www.aquarticles.com/articles/man ... heart.html

The same as yours. I used mine for ornamentals too, instead of the tera min flakes i Used wardleys tropical flakes (bought it cheap in bulk) I left out the beef liver (as it can make water go cloudy) and the trout chow (because i didn't have any at the time).

It took me a couple of stores to find just plain paprika, as stores were selling hungarian paprika and smokey paprika, etc Next time i make it, i will use spirulina powder and paprika (as spirulina has much higher beta carotien and other stuff) and i am sure the fish wont mind greed food....Also i will be adding some garlic, as its supposed to be good for the fishes immunity, and it stimulates appetite

I will be trying to get a grinder for next time, as i grated the beef heart (TOOK AGES) But i still have heaps left...

Oh and the ingredients may be for a different brand of algae wafers, as i don't know what brand you have. But looking at a couple of diff brands they are pretty much the same, just in slightly diff order


BUT if making fish food cater it to your fish, eg food for silvers could contain plant matter, but if fed to barra i doubt they would be able to digest and benefit from it ...