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Guest Ulatawa

Free (?) fish food

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Guest Ulatawa

A further extension of the Aquaponics system is to breed worms to feed the fish.

A kilo of composting worms sells for around $50. Apart from some containers to grow them in, this is about your first and last cost. I hate polystyrene with a vengeance, but heaps of poly vege containers are normally available from your local store for free, and if they've already been made and used, its not all that environmentally bad to use them again. Worms need aeration, and the best poly containers I have found for worms are the ones for beans. These have plenty of aeration holes and slots, and are keyed so that they stack well.

When fed a decent diet the worms will double their number and/or weight every two months. For maximum growth I have found that horse poo gives the best results, followed by (singly or in combination) cow, sheep, dog and cat poo, vege scraps, shredded newspaper and cardboard, coffee grounds, smashed egg shell, and even the contents of the vacuum cleaner bag. Avoid onion, citrus and meat.

There's a huge amount of advice on the web for worm farms and I won't attempt to duplicate that here.

However, assume 10kg of composting worms. On average these will produce a 160gm increase/day, available for fish food. Multiply this by whatever requirement you have for feed, and not only will it be substantially cheaper that purchased feed, there will be a considerable reduction in your landfill contribution. Chuck all your organic household waste into the worm farm.

Buy two kilos of worms and you'll have 16kg in 7 months. I've tried these with my 200 Silver Perch (35-50mm) and its a feeding frenzy. For the trial I tossed the worms into the blender for a brief burst, but as the SP grow this won't be necessary.

I suspect that there should be some par-boiled greens also to balance the diet.

Read some data on composting worms and learn that they have an incredible capacity to eliminate pathogens and toxins.

I'd like to hear from anyone who has tried this addition to the system.

I'm also aware that some large-scale Aquaponic systems collect dead animals (e.g roadkill) and suspend these in nets above the ponds. The carcasses become fly-blown, and mature maggots drop off into the waiting mouths of the fish. Might sound gruesome, but many Asian cultures have used mixes of domestic poultry, pigs, cattle and pond cultivation of fish for 4000 years, with no apparent ill-effects. This can be extended of course to the similar use of human waste. I'm not necessarily suggesting that you rig up a dunny seat over your fish tank, unless your marriage is already on the rocks, but just maybe we're seeing the sort of peanut intolerance, attention deficit disorders, return of TB and related problems because we're tending to sanitise ourselves to the extent that our immune systems aren't developing as they once did. And because few kids get dirty anymore, that exacerbates the problem. And we're told that commercial chicken doesn't have hormones, but (along with beef) its laced with antibiotics.

And remember, the average box of veges delivered to your local Woolies or Coles has travelled over 1000km, often passing the area where the food was originally grown twice. Airfreighted strawberries from California, and frozen potato chips from Belgium (I joke not) are indications of consumerism gone mad.

Legislation won't change this. But when water charges reflect the real cost of having it available at the tap, and when power prices become 3 times their current level, and when petrol and diesel rise to $4/litre, the dollar will drive the changes.

Finally, a word about biofuels. Firstly the word defines all current fuels. Coal and oil are derived from plants, albeit a long time ago. Secondly, for the UK as an example, to replicate its current liquid fuel needs from plants would need 25 million hectares of arable land. Unfortunately the UK only has 5.5 million ha of farm land, and all that is used to grow stuff called food for human and animal consumption.

In brief, the upshot of the so-called biofuel revolution is that it is often more profitable to grow crops for conversion to fuel than for food. Take this to the next level. Multinationals will become increasingly involved, as is beginning to happen with increasing acreages of GM modified rape seed in the UK and the Continent. First result is that less acreage will be available for food production, and less water will be available. So food prices will rise, as has happned already in Mexico as an example as more and more maize is being converted into fuel for Hummers and less into tortillas.

And there's a more terrifying phase. Palm oil is hugely productive on a hectare basis and its conversion into fuel is relatively simple and cost-effective. Already we see increased forest destruction in Malaysia, Indonesia and Brazil to plant more palm oil. The demand for so-called Biofuel could result in the greatest destruction in natural forests that has occured since the last Ice Age. All so that Mum can drive her Range Rover to take the kids to pre-school, and ****** the planet and the starving billions.

Max H

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Hi Max,

I've tried worms.....and various other alternative foods for fish.

While I agree that worms are good, my preference is for Black Soldier Fly larvae and duckweed.

BSF larvae are easier (and much faster) to produce than worms and the resulting 'castings' can still be used for worms after the larvae have reduced it. BSF larvae are also much easier to harvest than worms.

Duckweed is another excellent fast food for fish.

Worms, BSF larvae, duckweed......I love them all.

Gary

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Gary,

Have you tried mealworms? At the moment I have a culture which is going like a steam train. I seem to recall that when I kept tropical fish about 20 years ago that mealworms were considered OK but only in small doses due to heavy chitin in the skin?

Jim

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Hi Jimbo,

Yes I have tried mealworms but without a lot of success. I bought a small tub in an aquarium shop and reared them to the beetle stage.

All I ever achieved was a stinking mess.

I found that I could breed blowfly and housefly maggots but they kept leaving without notice.....and the baits were obnoxious to say the least.

Then I discovered Black Soldier Flies. I find that I can breed them in large quantities....in just days......and they harvest themselves. And the "castings" make excellent soil condition or even worm bedding.

Gary

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Guest cumquatmay

My friend who grows fish commercially said something about is ages ago.

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Hi Cumquatmay,

There might be something in that theory. I must do a bit of reading around to see if I can find anything along those lines. My fist guess is that if there is anything to the theory, it would be based on what the worms are fed.;)

Muzza

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Guest cumquatmay
Hi Cumquatmay,

There might be something in that theory. I must do a bit of reading around to see if I can find anything along those lines. My fist guess is that if there is anything to the theory, it would be based on what the worms are fed.;)

Muzza

I've asked him to explain. I think it was a diet that was only earthworms. Perhaps mixed with other things it would be ok just like people who only eat cheese get heart attacks. May.

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Guest cumquatmay
I've asked him to explain. I think it was a diet that was only earthworms. Perhaps mixed with other things it would be ok just like people who only eat cheese get heart attacks. May.

I asked him if he had a website to explain it:

"Not off hand, but from several years of raising Guppies we definitely

found fish grew 'bull-chested' if fed too much grindal worm (similar

to whiteworm but about 10 mm long at max.). Whiteworm are reputed

(again no citns) to be 2 to 4% fat, which doesn't seem high. Some

breeders put it down to fish loving to chase the live worms, and just

eating too many. However, the other premium live food for fish is

brine shrimp (Artemia saline) nauplii. Fish will really pig-out on

these, and never develop the same problems as with worms. Estimates

of fat content of A.salina vary considerably from negligible to very

high. Probably the effect of worms will also vary from one fish

species to another (and A.salina fat content may depend on the

life-stage they are at and the variety). As with most things, you

will probably run into trouble if you give any one type of food in

excess.�A variety of veg, cereal, meat�and different live foods would

be best. We used to feed Brine Shrimp naupli, Grindal worms, Beef

Heart (put through a blender and freeze into cubes, then scape some

into the tank when required) Flake food and wheatgerm for variety (we

also used ground rabbit food pellets and dried, ground whole sheep at

other times). Worms would be a valuable part of the diet, just not

too much!"

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Thats interesting, I know that my Jade and Silver Perch go crazy when I throw a handful of worms into the tank. I don't do it often because I do not have a very good worm farm as yet. Mine get mostly pellets and left over lettuce leaves.

Murray

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Hi Daniel,

I'm planning to write an article on Black Soldier Flies for the next issue of Practical Aquaponics.

In the meantime, take a look at http://www.duckweed.info/duckweedblog/archives/2007/02/black_soldier_f.html

I've been harvesting BSF larvae for some time now......almost got it down pat.

Feel free to ask any questions and I'll do the best I can to help you.

Regards......GaryD

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Guest sunnyside
Gary,

Have you tried mealworms? ..................mealworms were considered OK but only in small doses due to heavy chitin in the skin?

Jim

About the same levels as your yabby shells. Especially high in the Giant Mealworms.

Certainly causes problems with animals, yabbies, and lizards (that I know of).

Have you tried using molted worms to avoid the chitin? http://www.chameleonsdish.com/insects/molted.htm)

Chitin is used for wound dressings, sutures and as a fertilizer for plants. It's also soluble in vinegar - though I can't suggest how that'd be used to remove the chitin from unmoulted mealworms:rolleyes:

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The only problem with wanting to use moulted mealworms would have to be the hassle of sorting to collect those which have just moulted. My cultures are still going like crazy- literally thousands and thousands of grubs in all states of development. As I don't actually have fish in the AQ setup yet it is all moot anyway. However we do feed the occasional mealworm to our frogs and the ones which don't escape into the undergrowth in the frog tank seem to be rapidly eaten.

I am now going off to check my cultures and to see if I could select moulted worms when the time comes.

Given the numbers which would be needed for a couple of hundred silver perch or catfish I think I will have to get a "self harvesting "black soldier fly colony going for usable quantities of live food.

Checked the cultures- no way I could be bothered looking for moulted mealworms in quantity- simply very few visible at the moment- perhaps they could be provoked into moulting at specific times in some way- more research needed!

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Guest talking2u

I use (Gambusia affinis) a Mosquito fish they grow about they grow 2 inches are prolific. My fish love them!

The fish I raise is Tilapia I only keep males. several reasons but the females will brood 230 babies at a time.

so a few of them would be great in your tank. jan

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Hi,

Tilapia are a banned species in most parts of Australia.....and so are Mosquito Fish.

Tilapia have been introduced into our river systems by aquarium operators who have disposed of them inappropriately or by people who decided that they'd be a good food species to have in Australia.

Mosquito fish were introduced with the idea that they would eliminate a range of problematic mosquito species. Not only did they not achievet that goal, but they have become a pest species themselves.

If I lived in your part of the world, I'd farm tilapia but, aside from the bio-security issues, we have too many good freshwater species in Australia to even consider them.

Gary

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Hi abbabba,

BSF are a bit quiet at the moment.....their breeding cycle is temperature-sensitive.

Just start to gather up kitchen waste in a compost bin......I use one those bins with a square base and lots of holes in it so that the female flies can get into it to lay their eggs.

When the days warm up a bit, the BSF will find your compost bin.

You'll know it's happened when your pile of kitchen waste begins to quickly subside. You'll reach the point where you'll have trouble keeping up with them.......then it's time to begin harvesting.

Gary

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Thanks Gary,

I will look out for them. The only worry I have now is, do the BSF live here in Victoria? I did a bit of a reading on them in the mean time, and it seems they prefer warmer climate. Looks like I will have to wait till summer to see :rolleyes:.

abbabba

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Hi abbabba,

The species of Soldier Fly that we're talking about is Hermetia Illucens.

While it's native to America, it is believed to have been translocated to Australia during the Second World War.

It will be found all over Australia.....including Victoria.

Gary

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I wonder if there's any black soldier flies in Malaysia... Is there? I'd like to try it too... Should I just put out a bin full of kitchen waste to attract them? And where are they mostly found? Are there any in the city or should I try looking for them in rural areas? Do they help pollinate plants too?

I was thinking of building a bee house for solitary bees to attract and cultivate them for pollination. No bee hive for me, I had enough of being chased by bees while picking fruit in my orchard.

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