Stocking Rate

[justafarmer]

Hello everyone,

I have a 1500 litre pond in which I'd like to try to grow some Golden Perch fingerlings.

What stocking rate should I use? Remembering that I would hope the fingerlings grow to a good size, I should obviously start off with a small number so as the total mass of fish increase with growth I end up with an optimum environment. As I have to be careful I don't overpopulate initially, what number of ingerlings do people think I should begin with?

Mike

[Murray]

Hi "Just a farmer"
Welcome.
In your situation I would start the calclation with an assumption of 1 fingerling per 20 ltrs of water = 75 fingerlings.
You will most likely lose a few fingerlings, it happens, and is there going to be any active circulation/aeration, bio filtration, of the water in the pond.

If the pond water is going to be static then I would think that 10 to 15 fingerlings would be an optimistic limit. In a static body of water that size I would not expect to see more than 3 or 4 grown Perch happily inhabiting the pond.

Food supply for the fish would be a problem. Golden Perch are difficult to get onto pellets and like a diet of insects/worms etc. That is another factor to keep in mind and will limit the number of fish you can reasonably expect to successfully have inhabit a pond of that volume.

If on the other hand, you were to be raising fish in a Aquaponics system, ie, a 1500 ltr tank with grow beds attached, you could reasonably expect to start with 75 to 100 fingerlings, and successfully grow them out to plate size.

I hope that helps a little.

[justafarmer]

Thanks, Murray.

I have a conservatory in the floor of which I've buried a 1500 litre round cattle trough. Above it, I've formed a smaller (75mm deep by 1.5m X 1.0m) triangular "pond" lined by a butyl pondliner which I've filled with river gravel. This had to be shallow due to the limitations of the level of the rim of the trough and floor level of the conservatory. I plan to move the water from the trough through a biofilter to the overflow pond to cascade back into the trough. I'm hoping I can grow some plants in the gravel "pond" - a kind of shallow growbed.

I'm hoping the lack of depth in the growbed will be compensated for by the biofilter.

You may have guessed by now that this is an "aesthetic" system - the conservatory is actually the entry foyer of my extension and the look is a natural stream-type scenario - the rim of the trough will be disguised by stone, grass, etc. The plants will initially be non edible, but if I discover some good looking, fruit bearing plants that would be good.

Do you think this system would accomodate 75 to 100 Golden Perch fingerlings? I realise they don't take pellets readily, but there is a crowd in NSW that supplies fingerlings "weaned onto pellets". What other fish species would people recommend?

As I'm a novice to aquaponics, can I ask what may be a stupid question - if plants in growbeds have a constant stream of water passing through the gravel, will root rot eventually set in? In my situation, the roots will be constantly immersed in a depth of water to 75mm (albeit in gravel) - will this limit the kind of plants I can use?

Cheers,

Mike

[Murray]

Hi Mike,

I'm hoping the lack of depth in the grow bed will be compensated for by the bio-filter.The bio-filter will be a big help and if it has enough capacity it will be fine.

this is an "aesthetic" systemI have a Landscape Gardener friend who is embarking on a very similar project for a client. It is a wonderful idea.

Do you think this system would accommodate 75 to 100 Golden Perch fingerling's ?By the sound of it, yes....but be prepared to remove some of them as they grow. It would be much safer to go to the very low side on stocking numbers until you get the feel of things. It is so easy to kill fish when you are getting started. (I reckon I hold the world record for fish kills) Make sure you test the water regularly..... daily is a good habit.

the roots will be constantly immersedIt is possible for this to work if you use plants such as water lilies or some similar type of plant. The other way is to make sure the dissolved oxygen levels in the water are very high by adding heaps of air to the water entering the grow bed/s. Some large commercial aquaponics systems operate this way using "Floating Raft Technique" The plants are grown on/in rafts of foam floating on the water surface. The plant is inserted into a hole through the raft with the roots dangling through into the water below. Root rot is avoided by the water being highly oxygenated, and constant water movement/circulation.
However, in small domestic systems "flood and drain" has proved to be highly successful. Flood and drain will deliver healthy plants and fish.


there is a crowd in NSW that supplies fingerling's "weaned onto pellets". What other fish species would people recommend?I would love to have some Golden's...especially if they are weaned etc. I have not heard of anyone successfully raising Golden's in tanks as yet... I am sure someone will work it out very soon. Evidently it is always a feed issue, so if they are really already on pellets there should not be a problem.
Please send me the contact details....I want some. :)

If you wanted to be safe, Silver Perch or Murray Cod are good. Silver Perch are hard to beat....easy and reliable species.

[fishfood]

Thanks, Murray.

I have a conservatory in the floor of which I've buried a 1500 litre round cattle trough. Above it, I've formed a smaller (75mm deep by 1.5m X 1.0m) triangular "pond" lined by a butyl pondliner which I've filled with river gravel. This had to be shallow due to the limitations of the level of the rim of the trough and floor level of the conservatory. I plan to move the water from the trough through a biofilter to the overflow pond to cascade back into the trough. I'm hoping I can grow some plants in the gravel "pond" - a kind of shallow growbed.

I'm hoping the lack of depth in the growbed will be compensated for by the biofilter.

You may have guessed by now that this is an "aesthetic" system - the conservatory is actually the entry foyer of my extension and the look is a natural stream-type scenario - the rim of the trough will be disguised by stone, grass, etc. The plants will initially be non edible, but if I discover some good looking, fruit bearing plants that would be good.

Do you think this system would accomodate 75 to 100 Golden Perch fingerlings? I realise they don't take pellets readily, but there is a crowd in NSW that supplies fingerlings "weaned onto pellets". What other fish species would people recommend?

As I'm a novice to aquaponics, can I ask what may be a stupid question - if plants in growbeds have a constant stream of water passing through the gravel, will root rot eventually set in? In my situation, the roots will be constantly immersed in a depth of water to 75mm (albeit in gravel) - will this limit the kind of plants I can use?

Cheers,

MikeHi Mike i am shore everyone would like to see progress photos

[justafarmer]

Here is a photo of the work in progress. I will get that link for you Murray.

I just ordered a Resun 8,500lph pond pump from ebay. A little worried that I might have gone too high with the flow rate as I cant find a biofilter that will take all that. I calculated the rate using a web-based calculator taking into consideration stocking rate, pressure head, biofilter, sunlight, depth of water at the top of waterfall etc etc, but perhaps went overboard. I'm thinking I'll use a "splitter" to divide the flowrate - perhaps use one half to create a circular current in the trough so there is a vortex effect and place the pump centrally to pick up fish poo and other solids. Other half through the biofilter and on to the overflow pond.

Think I'll use your suggestion of aerating the water to the upper pond, Murray. Perhaps a 90mm PVC pipe with holes drilled in the lower end (under the gravel level) to take the incoming water from the trough so I reduce the chance of root rot under the 75mm of gravel in the upper pond.

In terms of plantings, I'm thinking papyrus, rushes etc. Not very consumable but if I can get some suggestions for perrenial plants (don't want that vegie garden maintenance problem inside the house - later I'll do external aquaponic setup) that bear fruit, I'd love to have a "productive" and "aesthetic" system!

This post is becoming less about fish and more about a newly established system, so perhaps it should be transferred to the right forum (?)

Cheers.

[justafarmer]

Here is that link, Murray:

http://www.aquablueseafoods.com.au/golden-perch-aquaculture.shtml

[Martin A1]

Hi Everyone,

Aquablue is the hatchery operation in NSW that you just have to visit! Murray if your heading to your daughters this Chrissy then you must make the effort and get to Port Stephens NSW (ie just North of.. near Tea Gardens actually)

I spoke with Neil, the operator, only last week... very nice bloke and I think he is on board in supporting us backyard sustainability like minded!

This is where my next batch of Silvers is coming from... without question! Maybe they should be half Yella's?? If only I could deal with salt water snapper and Mulloway in my backyard!!!

I love the thread justafarmer! Keep up the great progress mate and keep us posted! I reckon' that there are lots of hatcheries that will be able to sell you fish trained on pellets.

Attached is a directory including hatcheries that may give you some other options closer to the border.

Enjoy

[Murray]

Excellent info. Thanks for the link Martin A1.

[GaryD]

Hi Justafarmer,

I must have been asleep when this thread started. Your system is looking great.



I just ordered a Resun 8,500lph pond pump from ebay. A little worried that I might have gone too high with the flow rate as I cant find a biofilter that will take all that


Don't concerned, you just need a bigger bio-filter. A 200 litre drum filled with appropriate media will work a treat on your 1500 litre system. You can always bypass any excess water flow back into your pond to keep the water moving. Remember that good dissolved oxygen levels (essential for healthy fish) are the product of adequate water movement.

A trickling bio-filter of the capacity that I've suggested will help to offset any issue around the depth of your growbed.

I'm not entirely clear on the set up of the grow bed. If it has water in it at all times you will have a problem with root root and you'd be better off to grow water plants like kangkong or Chinese water chestnuts. If you can provide a clearer description of how this grow bed works, I'll endeavour to make a better recommendation. (It's 4.00am).

I'd recommend a fish species other than Golden Perch for your first attempt. Given your cooler winter location, I'd go for Silver Perch until you get some experience under your belt. You can then consider other species like Murray Cod or Golden Perch. If you can rear fingerlings in optimum conditions during the off-season, you could even think about two crops of fast-growing fish......like Rainbow trout in Winter and Barramundi in the hot months.

GaryD

[justafarmer]

Your recent comments have encouraged me to post some update pics of my work in progress.

The goldfish I have (all eleven of them) are happy as larry in a warm conservatory and eat all the time.

The pond got into trouble in the first 3-4 weeks as expected, with an algal bloom to the extent I couldn't see the fish until they were right at the surface. I then installed by 8500lph pump which now runs constantly feeding the river gravel "grow bed"/ "stream". It's taken 3-4 weeks but the water has cleared remarkably - I can see the bottom of the tank.

This has been achieved with a 75mm deep grow bed even without a biofilter. I've now bought one but it's gigantic - 650mm high. I will try to bury it in the soil. I suppose I'll need it to cope with fish waste once I add to my current stock.

Plants in the growbed were initially ornamental - papyrus, etc. I've added some bokchoy and recently my painter was so excited by the project, he donated some lettuce. I've planted these in the constantly running stream/ grow bed but I'd expect root rot and leaf rot soon, but what's happened first is that the leaves of the bokchoy are being eaten by something - holes in them. A separate post under Plants in this forum has given me some suggestions for safe remedies. More suggestions welcome as I don't want to kill my goldfish. I've now been given some tomato plants which I'll try to grow. If I get too many plants deteriorating I might decide to install the pump on a timer - but it won't please the wife - "streams don't run intermittently".

I don't anticipate that my 80 litre grow bed will provide the nitrogen absorbing capacity for a 1300 litre tank, but it seems to be managing the job well probably due to the small number of fish available. I expect this will not keep up if I proceed to add 75-100 SP fingerlings as Murray suggests.

I recently found a small 500mm X 500mm X 200mm tank (damaged water feature base) which I will add as a grow bed. I'll dress this up with some vines/ferns on the side to beautify it - remember this is supposed to be a "natural - looking" aesthetic system. I'll place this close to the edge of the planter box where this system sits so I can "harvest" the produce more easily than from the current ground level stream grow bed.

Love the idea of kangkong and water chestnuts. Somebody local suggested watercress. Hope the pics clarify the system. The blue dairy tubing (used for dairy washups) carries water from the tank to the 75mm stream/growbed. I've buried the end under the gravel so the is little oxygenation at this point - aesthetics again. The overflow than cascades into the fish tank - I'm hoping this will be sufficient for aeration (may not be once stocks increase).

Any more ideas for plantings will be appreciated.

Thanks all. Aquaponics is fabulous!!

[Murray]

Hi Justafarmer,
It is just amazing just how well a gravel grow bed filters the water as you have found, even though yours is a bit shallow.
Some how you will have to get it to flood and drain otherwise you will get the effects of root rot and brown leaves etc that you speak of.


I don't anticipate that my 80 litre grow bed will provide the nitrogen absorbing capacity for a 1300 litre tank, but it seems to be managing the job well probably due to the small number of fish available. I expect this will not keep up if I proceed to add 75-100 SP fingerlings as Murray suggests.Every system has to find it's own balance and you are correct in your assumptions. Once you see how well the veggies grow, there are never enough grow beds.(or fish)


remember this is supposed to be a "natural - looking" aesthetic system.Great if you can get it to look good for the lady in your life. My system is down the back beside the shed so I can be a bit untidy.....but it looks great anyway.
Sweet Corn goes really well in an aquaponics system, but may not be a good look so close to your front door :) It would be convenient though ;)

[Martin A1]

Clear some room in your backyard justafarmer because I can see a second system coming up....... once you start you just can't stop!

You definitely have the bug mate! Great to see the updated pics thanks!

I'd keep your decorative indoor system decorative (as you have done so wonderfully) and start a larger scale veggie production unit in your backyard.

Make sure you point your painter to this site.. the more of us onboard the better!