5 replies to this topic

[dave06]

Hello All,

I'm looking at buying a 9000L aquaculture tub 3500 Diameter x 1280 H .

Can someone tell me what stocking level I shoud have for Barra and Trout ?

Looking at raising them to eat.

I'm not really interested in aquaponics side (ie water use/irrigation) -

Filtration will be very good.

Cheers

Dave

[mattt]

easily do a couple hundred fingerlings to plate size in a season in that

[werdna]

Stocking level is dependant on the limiting factor, in this case it will be filtration.

In aquaponics you look at 25 fish per 500 litres of grow bed, which is the filtration.
You havent mentioned your filtration, so a guess would be difficult.
Also I doubt many people on here would have much idea on aquaculture.

Very roughly, you could say 25 fish per 1000 litre for fish up to 500gram which is roughly plate size.
So using that theory you could have between 200 to 250 fish, maybe 300 or more if filtration is excellent.

At the end of the day, it might just be a hit and miss thing, start with 50 and increase by 50 every 6 month cycle until you start getting ammonia/nitrites appearing in the system.
That will tell you when your filters arent keeping up anymore, but even then there are other factors that need to be considered that could increase ammonia, too much food for example.
You are going to have to start with a lower stocking density anyway to give the bacteria in your filter time to build up.

Good luck with it, sounds like a tasty venture

Andrew

[Ivan Sng]

Well yes, the stocking levels is determined by how much filtration you have... I think you will need to setup somewhat like an aquaculture setup with a swirl filter and biodigester (I think), etc. Not an expert on aquaculture setups so don't quote me. Barra and Trout produces lots of waste when you are growing them out and if you do not want to condition the water (ie heat or chill) that you have a window of about 6 months each to grow out barra or trout... and if you decide to condition the water (ie heat or chill), you cannot mix barra and trout as they will eat anything that fit into their mouth, and hence you cannot mix smaller fishes with bigger fishes as well unless you want the smaller fishes to become food.

I am not sure you understand how much water changes you will be looking to maintain low nitrates level... 20% of 9000L??? And since you intend to eat the fishes, you don't want to use artificial chemicals/chemically treated filtration media to reduce nitrates since you may indirectly be consuming those chemicals.

Hence this is where aquaponics comes in handy, (not sure about your comment about water use; you might have been misled), there are no water changes required, as the plants/vege remove the nitrates... Just topping up for evaporation losses and plants usage from growing edible food....

It so happens that Backyard Aquaponics in Jandakot are getting rid of a big setup (tank, swirl filter and biodigester), have a chat with Joel. I think if you don't like the aquaponics aspect of it, then the tank, swirl filter and biodigester is all you need...

http://www.backyarda...i...f=10&t=9745

And oh yes, I think if you treat Mattt nicely, it might give you some good ideas... He might be your neighbour...

Edited by Ivan Sng, 27 May 2011 - 10:39 PM.

[dave06]

Thanks All for your input.

Which fish (barra vs trout) require the most room - or is it the same ?

[Ivan Sng]

I think they are about the same. Trout is a bit more sensitive to poor water quality and does not like uneaten food settling at the bottom of the tank. They will not eat settled food but the food will foul the water, could cause the trout to die even before you see an ammonia reading... For this reason, I only use floating pellets for both barra and trout.

Also bear in mind that this year is a bad year for many of the fish stocks in Perth. Trout stock is limited and may be expensive. Barra is sounding like it could also be expensive to buy when the warmer weather hits...