Backyard Aquaponics
A place to discuss aquaponics

My large flood and drain system is at the stage where I need to put in a new crop of fish. As it's coming into winter I was thinking about putting in some trout just for a change. I have not grown trout in an aquaponic system before as I have been concerned about the fragility of them a species.

Has anyone grown trout in an aquaponic system before?

Joel,

As I'm only new to aquaponics and in the throws of starting to set something up, I have no info on growing trout or any other fish for that matter.
However I do have a question about "new crop of fish" as you put it.

Do you replace all fish with new fingerlings? Or do you add new fish to existing large fish? If you do replace all the grown fish with fingerlings, what does this do to the nutrients for the growbeds? Do you need to add plantfood to keep the beds growing for a while?

Similarly when you first start up with say four growbeds like in your system, do you start planting only one bed, and gradually plant (and flood and drain) next beds when the fish grow larger?

Karel

G'day Karel, good to see you here.

It's a great question that you ask, and the answer is that I do both. In my smaller systems I tend to keep a variety of fish of different sizes, and will stock with new fish as older, larger fish are taken out of the system.

However you have to be careful about the size of the new fish going into the system. If you have very large fish in a tank, then any very small fish added to the system will end becoming food for the larger fish unless you provide some cover for them like a small netted off section for protection. A tank can easily be sectioned off with netting to keep the large fish away from small fingerlings.

In my larger 4 bed system I stock the system with 100-120 fingerlings, all the same size. All grow beds are working at this stage, but I do supplement the lack of nutrient with a little seasol, and charlie carp into the water. Generally this supplementing isn't required for very long, perhaps once a week for 6 weeks, and only small amounts. Only a small amount is required because I replant all of the grow beds at the same time as re-stocking the fish, and so there isn't a great deal of nutrient required by the small seedlings at this early stage.

Once the large system is in full production and everything is growing well, I try to keep the four grow beds at different stages of growth, only ever harvesting one grow bed at a time, then replanting it..

As the fish grow larger the plants just tend to grow quicker and healthier.

A question on fish stocks - do you aim at any point to breed your own fish in a nursery tank? Otherwise I can't see the system being that self sufficient if you need to keep running off to a fish farm for fingerlings.

Cheers,

FF

Hey FF,

Ultimately, yes it would be great to be able to breed my own fish. However you can't do everything in life yourself, and perhaps I'm better off doing the things that I do well, and leaving the tricky breeding and rearing process to someone else who is skilled and set up for that.

Maybe one day.....

I'm with you Joel,, I got plenty of other stuff to do, I'll let someone else do it, and I'll be more than happy to pay the few bucks for 50 or so fish

Can't do everything yourself....

There's a bloke up the road who breeds fish by the 100,000's...he's quite happy to sell me 100 or so, considering he usually wouldn't bother with orders under 20,000.

It's an old arguement....kinda like should you make your own shoes or buy them.

You'll probably get them fairly cheaply to hey Corn? Always good to know a bloke...

I'm about to pay 400 bucks to have 150 semi mature fish delivered to me....

Am hoping so! I know that when he gets a huge order the price is around 20 -30 cents....so will see.

Do you have any idea how big they are when he sells them for 20-30c ?

umm nope....still haven't organised to go and have a peep at his setup.

Are you thinking they might be 'small enough to be sucked into pump' size?

Have me wondering now. Will hopefully see him tomorrow at the meeting tomorrow, so will ask him then.

Joel - I seem to recall you mentionning that your bloke gets his food from a supplier in Qld.

Is there any chance of you finding out and letting us Qlders know who this supplier is. Before I seriously consider investing in tanks etc, I would want to get a definite price on the consumables - namely the fish food.

Thanks.

You should register Guest

Woops - Was sure I had logged on before sending that message. It's me - Veggie Boy - Joel and Corny.

lol g'day VB

can get confusing if more than one 'guest' starts posting